Hello everyone, my name is Dr. Anand Kumar Sharma, my rank is 62 in CSE 2018, in this video we will be covering chapter 7 that is India's Demography at 2040 Planning Public Good Provision for the 21st Century. So this chapter is talking about the slowdown in the population growth of the country, how it is impacting the various states, how it is going to impact the provisions of the country of the labour force, the PFR, the health climate or the public good provisions, how they are going to impact it and how do we need to prepare it. So it is about the trajectory of the population growth and how we need to prepare for the population growth trajectory in the future. So it says India is set to witness a sharp slowdown in the population growth, although the country is going to enjoy the demographic dividend but states like south Himachal Pradesh, West Bengal have their TFR below the replacement level whereas the states like Madhya Pradesh, Jharkhand, Uttargarh, Rajasthan are above the replacement level but they will also be experiencing a significant decline. It talks about that the Dashlet TFR is going to be below replacement level by 2021 adjusted for sex ratio. The age distribution however India implies this work age population will grow by roughly 9.7 million from 2021 to 31 and 4.2 million per year from 2021 to 41. Also the proportion of elementary school going at 5 to 14 age is going to decrease though state needs to pay attention to the merger of the school and also prepare or the health infrastructure for the aging. So it shows that our growth rate has decreased from 2.5 percent during 71 to 1.3 percent as of now in 2011-16. Some states have their replacement level, TFR below the replacement level some states have higher than the replacement level but they are going to significantly decrease. So the replacement level is usually marked at 2.1 as discussed this has been decreased due to the effective replacement level adjusted to the sex ratio of the country. India has reached the current TFR of 2.3 and which is relatively low to the other countries. There is a wide variation in experiences of different Indian states. States of South India as well as Himachal and West Bengal have their replacement level as low as 1.6 or 1.7 whereas high fertility rate Bihar have a high TFR but they are sharply decreasing. So this development suggests that India is going to enter a new stage of demographic transition which is along with the demographic dividend. So this we need to prepare for it so they are preparing for it and hence there need to be make provisions in the policy for old age care, for school facilities, retirement, public pension, income tax revenue, retirement age all these needs to be adjusted to prepare for this demographic transition. Now we are talking about the national and state level population projection. So it says projected values for TFR for fertility rates for 2021-41 suggests that national level will continue to decline rapidly and will reach replacement level at 1.8 as early as 2021 and at 1.7 it will become stable. This will be close to TFR and this will be early in Jharkhand, Chhattisgarh and in Madhya Pradesh UP it will be in 2031 and some states have already reached this level. So this will have an impact on this assumption and this TFR assumption is based on the sex ratio adjusted because the number of women are less than the number of men. Now we talk about the population growth trajectory. Population growth trajectory it talks about the population growth. It shows that population growth will continue to slow rapidly over the next 2 decades growing less than 1% during 2021-31 and under 0.5% during 2031-41 which shows that there is a sharp decline in the population growth of the country which is the current trend seen currently in Germany and France. So since there is a given a state level differences in the TFR replacement level and the growth rate declaration there is going to be a significant changes in the impact of this policy on this stage. So this is we need to prepare for this impact there is going to be a change in the age composition as well. Since this is decreasing India it says that the share of India's young population from 0 to 19 has already started to decline and projected to drop from as high as 41% in 2011 to 25% by 2041 whereas the doubling of the old age population is going to happen from 8.6% in 2011 to 16% in 2041 when share of working population expected to hit 59%. With changing of demographic composition India's age structure by 2041 will resemble as that of China and Thailand. So it highlights that how the old age population is going to double from 8.6% in 2011 to 16% in 2041 which shows that India's age composition in 2014 is going to resemble China and Thailand as seen during the current decade. Since there is going to be witness a decline in share of young population for next two decades the demographic transition such as Himachal Pradesh, West Bengal or the southern would have less than one fourth of the population under age of 20 but one fifth or more population over the age of 59. Similarly in the states like Bihar, Chhattisgarh, MP and Rajasthan this population is going to share of young population all those will remain relatively high as large as 30% in Bihar by 2041. So all this demographic transition this is going to have a various implications. Now we will study about those implications. Implication is like the working age population. Working age population will start to decline in 11 out of the 22 major states. The labour force ratio that is 9.7 million per year is going to rise in 2021 to 31 and from 31 to 41 it is going to be 4.2 million per year the labour force will be added. The working age population will start to decline in the states of southern states Punjab, Maharashtra. On the other hand working age population will continue to rise through 2014 in states lagging behind in demographic transition that is MP, UP, Mehr. So rising population could meet now there is going to be a migration from those states where the demographic transition is yet to happen and not where which has already happened. So the people will migrate from states like UP we have to all the southern states because there is going to be a deficit and there is going to be an access. So this will minimize the access will meet the deficit which is there in the other states. There are many elementary schools since the 5 to 14 population is going to decline and there are schools so there is a need the population is going to decline so the government needs to instead of opening school need to consolidate and merge the school to increase the quality. Quality of the schools and elementary education we are not talking about reducing the funding of the elementary education but shift from quantity to quality and that has been done where there is a decline in the school getting population in states like Japan, China, South Korea, Singapore and Canada they have also followed the same model so we need to do that so has to have a more quality and efficiency of education. Then health care facilities states where the young population is increasing or the population demographic transition yet to happen the number of beds per population is very less. So we need to prepare for this rising population as well and on the population where there is going to be a aging in the southern state or the other state there is a need to focus on the geriatric care geriatric care means infrastructure and the facilities for the old age people the diseases are affecting these people we need to prepare for that also. Further it talks about the retirement age since India's healthy life expectancy at the age of 60 that has been increasing over the period for both men and men it is 12.9 years average that is 12.5 years for male and 13.3 years for female so due to aging population and increasing on the pension funding many countries have been raising their retirement ages such as Germany France and USA Australia they have increased their retirement age so India also need to since a life expectancy for both male and female at 60 is increasing India also needs to increase their retirement age this will be key to the viability of the pension system help increase labour force participation and older age group and hence perhaps a decade before the anticipated shift this will help in plan for advanced pension and other retirement provisions basically they are planning about the infrastructure as well as the retirement age pensions for the people so as there is less burden on the pension funds and more labour force can be created so that a more output can be created for the people and also a better output and better efficiency for the country can be created so this chapter is not merely an attempt to look at the changing population dynamics but it also talks about what are the policy revisitations we need to make to address the demographic transition which has occurred and which is about to occur in some state so as to meet the needs of the rising population aging population so that there is a less impact and less burden on the resources and this will help us so that the government policy intervention can cope up with this change now we will summarize the chapter India is said to witness a sharp slowdown in population growth in next two decades all the country as a whole will enjoy the demographic days state some state will start transition to an aging state by the 2030s a surprising fact that this population bracket in 0 to 98 bracket is already peaked due to sharp decline in TFR across the country the national TFR is expected to blow replacement late by 2021 working age population will grow by roughly 9.7 million per year in 2021 to 31 and 4.2 million per year in 2031 to 41 the proportion of elementary school going education that to 5 to 14 children is going to decline so there is a need to shift toward consolidation and merger of the schools to have a better quality and efficiency of the elementary education and also the policy makers need to prepare for aging that is for the health infrastructure as well as increasing the retirement age to reduce the burden on the pension and other resources this way this chapter talks about the changing population dynamics and how to cope up with what policy interventions we need to make to get prepared for this change and so there is a less burden and also the government is well prepared for that thank you subscribe to our channel and click on the bell icon to get latest updates on upcoming videos


All righty, welcome back to operating systems. So yeah, before anyone asks, the curving down or curving up or whatever, that was a joke. I didn't even scan them yet. Like I didn't even actually look at them aside from like a few. So don't worry about it. So all the exams got scanned this morning. TA is currently grading it as we speak. They'll be back to you ASAP, hopefully by Monday, something like that. I don't know. They all have their assignments. They are all currently grading. They might actually be asking me questions right now, but I'm doing a lecture. So today we get to continue our journey of file systems. So we've all used file systems before. So there's actually a usual layout we have for POSIX systems. It actually has a name. It's called the FHS or File System Hierarchy Standard. Yes, we are very good at creative naming. Look something like this. So at the top of your entire file system, you have a directory called root, which just begins with a slash. And that is an actual directory. Then past that, the directory has a bunch of other things in it. They're all given by names. Likely in this case, these are all represent other directories. So within root, there's a bin directory. There's a dev directory. There's an ETC directory that usually has config files. Then there's like your home directory. So if you're on the UG machines, you'll have your own home directory. So in this case would be a subdirectory of that. Mine would be called john and then you'd have your files in it. So like todo.txt or something like that. There's also a specified slash mount and that's where whenever you plug in USB drives or something like that, they should show up in this directory. So all of our processes, they have something called a working directory that we've probably been dealing with forever. So in this case, if my working directory is currently slash home slash john, so I'm in that directory, what is the relative path of todo.txt if we remember what a relative path is? So if I'm currently in the folder john, what do I have to do to get to todo.txt? Yeah, dot slash todo.txt or just todo.txt because I'm already in that folder. So that's relatives directory. It's relative to wherever you are. Dot represents the current directory and dot dot is one directory back. So what about to the USB folder? How do I get to the USB to folder relative to john? Yeah, so relative to dot john, if I do dot dot, I go up to home, then slash dot dot again. Oh, sorry, FM? Yeah, yeah, then slash dot dot again brings us to here and then we can go to slash mount slash USB. So it's a bit of a trick, but those are relative directories. So to do dot txt relative, it could be dot slash to do dot txt. Sometimes you want absolute paths. So these are all called paths. Absolute paths will begin at the root and then get you to whatever file you want. So the absolute path for to do dot txt is slash home slash john slash to do dot txt. USB relative was dot dot to go up one, dot dot again to go up to the root and then slash mount slash USB or in absolute terms it would just be slash mount slash USB. So any questions about that? We've kind of dealt with file systems the whole time. You'll actually see what these things represent in lab six and while we're talking about it. So there are special symbols here. So dot, like I said, dot represents the current directory and dot dot represents the parent directory. So do we also know that in Linux, have you noticed that when you ls and stuff, any file that starts with a dot you can't see, it's like a hidden file. So in your git repository, you don't see it, but there's a dot git directory that holds all the information about your repository and everything like that. And in Unix or Linux or macOS, everything like that. If the file name or directory starts with a dot, it's like a hidden folder. Well, that was just one big mistake. So in ls, there's always a dot and a dot dot and typically you don't wanna see them if you just do ls, it's kind of useless to see them. So you just don't want them displayed if someone types ls. So a programmer was like, well, that's like two cases, that would be two if statements. That's silly, I see some commonality there. So I'll cover both these cases with a single if statement. So I'll just check the first character and if it's the first character, if the first character is a dot, I'll assume they meant it's dot or dot dot and I just won't show it and that was it. And that's why anything that begins with a dot is a hidden file because some programmer decided to be clever in like the 60s or the 70s and that was a bug that became a feature. So fun fact. So the other special symbols is tilde and that usually represents the current user's home directory. It's also held in an environment variable called home. This case, it would probably be home slash john and relative pass are calculated for the current working directory. Each process will have its own current working directory and it will also be in this environment variable called PWD or print working directory. So when we're accessing files, so far we've just accessed them sequentially and we haven't talked about how to randomly access any byte in the file unless we like M map it if we paid attention to that which we didn't really have to but for now we just know how to access a file sequentially. So whenever you open a file and you do a read while you are advancing a position inside the file so every time you call read you just read more bytes from that file and you don't get any duplicated bytes so it just keeps on going and going and going sequentially and if you do a write well they're just appended to the end wherever you currently are in the file. So if you do a write system call and you write hello and then do another one that says world well then you'll get hello world it'll just be appended on to the end and the kernel has to keep track of where you need to write those bytes in the file if it represents a file. There is a way to do random access and for random access that means you can read and write anywhere in the file and for that a specific position the file is required for each operation so you need to say if you're doing random access what byte in the file do I actually want to get read or write. So we kind of well we went over the open system call before so it just takes a path name some flags which can be like open it for read write open it for writing, open it for reading only and there's also another flag here that it's called oh append so by default when you open a file and you write to it it just writes to the beginning so if there was data already in the file it would just overwrite it so if you add a flag called oh append that means that any writes you do to that file descriptor that represents the file will just go to the very end of it. So the only way to modify essentially the where in the file you read and write system calls are going to read and write from is with this else seek system call which we haven't seen yet so it takes a file descriptor and an offset so an offset is just the number of bytes either to move this pointer so either negative, zero, one, two, whatever how many bytes and then the third parameter is wence so wence just means what this offset is relative to so there's a few options for this wence parameter it's basically just like an enum in C but it's kind of bad so there's three options seek set is like an absolute offset so that is just from the beginning of the file no matter where the pointer currently is so if I say wence is seek set and I set the offset to 16 that means it's going to change the position 16 bytes into the file from the beginning if I do seek current that's wherever I'm currently reading from so if I set it to seek current and hit an offset of minus two it means wherever that current position is I'm just going to go back two bytes and then I can reread that same information again and finally the other one is seek end so that's relative to the end of the file so seek set is relative to the beginning of the file seek end is relative to the end of the file so if I want to just go to the very end of the file I could go to seek end and an offset of zero so it takes me right to the end of the file so any questions about this, yep so the question is if I do a negative offset will I get an error or will loop around to the end so you can do a negative so if I do a negative offset but I'm relative to the end of the file that would be within the bounds of the file it'll give you an error if you're not within bounds of the file yeah so if I did seek end in a positive offset that would probably give me an error but if I did seek if I had a positive offset and I went to the seek set it would probably be within bounds unless I went over the file but it will make sure you're within the bounds of the file so any other questions with this because this makes it even more fun once we involve forking again so forking is the bane of our existence so here is the API for accessing a directory which we kind of which you did do in your lab so open directory, readdir so we're gonna see how these actually work under the hood in lab six but here's just an example just so we remember how we print directory content so this opendir well it wasn't anything special it actually opened a file descriptor if we S traced it and then this is how we just read everything in directory so in lab six you will be making your own directories from scratch and you will be told what file system format to actually use so here is what is stored in the process control block so remember that's in the process control block that's information about your process so that would be the processes page tables it's threads and it's open files I just said before so here is where we become explicit so inside your process control block there's going to be file open files and they're just going to be a big array so in this case I have the process control block for process one and it has three file descriptors zero one and two which our friends standard in standard out standard error and they actually just point to things so I told you before you can think that they just point to things so this is where we can see what they actually point to so they will point to a structure that keeps track of the current position that this file descriptor is currently at in this file the flags so if I have it open for read write write only read only and then this thing called a pointer to a V node and a V node just represents any resource that you can actually read and write bytes from so the full file descriptor represents a whole bunch of different things the V node would in the case of a real file point to that real file on the disk so you can have multiple file descriptors that point to the same file that have a different internal position so if I access it through this file descriptor it might start accessing it from the beginning if I access it through another file descriptor it might start accessing it through the end so in this case file descriptor zero of process control block one points to file a at some position with some flags file descriptor one points to different position different flags and a different file in this case file B and then process control block two while it can point to a different position independent of process one with its own different flags and its V node could also point to file B so file process one and process two could have file B open with different positions and when they read and write to it they have their own independent position so they would access it serially or sequentially if they just if they didn't do any L-seqs or anything like that so in this case one process would not affect the other so any questions about this? because yeah yeah so what dupe does in this case is it will take say you do a dupe two file descriptor zero and say two and one what that will do is essentially make file descriptor one point to the same thing as file descriptor zero so yeah so just point to the exact same thing the exact same position the exact same entry everything points to the exact same thing so yeah in that case if I read from file descriptor zero and then read from and then read like hello and then read from file descriptor one while it would keep on reading from that point it would read like world or something like that it just keep on going because they're sharing the same position all right any questions about that because it gets it's gonna get kind of weird once we start forking yeah so V-node is just a pointer to some structure that we can read and write bytes to so it could represent a real file, a socket, a pipe something like that it's just called a virtual node to represent you know it's virtualization so we're just representing something we can read and write bytes to the concrete version that we'll get into next lecture for real files and directories or something called an i-node and we'll see exactly what an i-node looks like in the next lecture but the super generic term that represents literally everything is just called a v-node or virtual node because well we like virtualize the things it seems to be one of our major solutions here so each process has its own file table in the process control block and a file descriptor is basically just an index into that table and that table is just a table of pointers that point to like a certain position, certain flags and then a v-node to represent what that file descriptor actually represents so what actually happens is when I pointed them to something what they're pointing to are entries in a global open file table and the kernel will maintain this and these are all the open files across all the processes in your system so that's how the kernel keeps track of literally every file descriptor that is open across all processes and how it would note that oh, does a process have the right end of the pipe open because it would be in the big global table? So we shortened the global open file table to a goff why we chose that name I don't know we're really terrible at naming so the global open file table or goff holds just information about like the seek position the flags and points to that v-node so which is just some resource that supports reads and writing bytes too so like I said again we'll see what that structure actually looks like if it's a real file it's called an i-node and that's tomorrow so the v-node again can represent lots of other things pipes, network sockets, shared memory whilst did we go over I think those were the main things that file descriptors represented right anything else I'm missing I don't think so yeah the kernel just depends entries to it so it's just dynamically resized so it's just however big it needs to be all right so now we have to discuss what happens with forking with this silly thing so remember what exactly what happens during a fork the process control block gets copied so specifically for us it would copy that local open file table so just that big array of pointers that point to entries in the global open file table so both process control blocks would point to the same global entry so that means if they're both sharing the exact same global entry if one process changes the position it changes it in the other process because while the position is part of that global open file table so that may or may not cause an issue usually it behaves how you want but it might surprise you so in this example both processes point to the same global open file table so both process one and process two their standard input file descriptor zero points to the exact same global open entry so if this represented like a file or something like that well if both processes are trying to do read system calls from that file and they're sharing the same open global open so say that file has it has two lines in it well what might happen is process one does a read system call it reads the first line which would advance the position to the end of the first line and then process two could do a read system call and then get the second line and then we're at the end of the file both processes would assume that that file is now empty so we read one copy of the file because they're sharing the same global open entry but one process gets one half and the other process gets another half so this might happen if you're actually forking and then sharing the same file descriptors which may or may not be what you want so any questions about that one because that will probably trip you up at some point in your life and you will have to remember this course and be like oh right they're sharing the position so the two processes neither one of them is going to open the whole file or you might get lucky and one process reads the entire file and the other process reads absolutely nothing so that also might happen so these are the gotchas so remember the current position that's part of the global entry and if you fork that gets shared between the processes so and also what will happen since that position shared if you do that L seek system call that changes the position well guess what since you're sharing the same entry if you change the position the other process it would also change the position in the other process because you're sharing the exact same entry so you could fork and then one of your processes could just set the position to the very end of the file and the other process might not know of it and then it would just assume that the file is just empty so sometimes you may or may not want this if you open the same file in both processes that would create multiple global open file entries so if you just call open or however you get a file descriptor through socket or something like that that will create a new unique entry in the global open file table so let's look at this example what would happen here if say for example this is one process it opens to do dot txt and then forks and then after the fork we open b.txt and assuming these are only open files how many local open files do we have in each process versus how many global open files we have and what is their relationship so I'll give you a few minutes with that and then we can discuss yeah so specifically how many would I have in each process so each process will have two local open files and in the global file table we'll have three entries so they'll be sharing to do dot txt and they'll have their own independent b.txt so just to go over what that looks like so let's say we have you know processed yeah let's call process 100 process 100 comes open has no files open whatsoever well if it doesn't open it would get a new file descriptor probably file descriptor zero if it has nothing else open so file descriptor zero would point to an entry in the global open file table because a new open system call creates a new entry in the global open file table so this would have its own position its own flags and then some vnode pointer to vnode that actually points to to do dot txt and that looks ugly so it has one entry in its local table that points to one in the global open file table so now if we do a fork while we're gotten used to this this would create a new process called 101 and since it's an exact copy of its parent it would have the exact same local file table so it would have file descriptor zero which points to the exact same entry so any questions about that? Just our good old friend fork so now at this point we don't know what process is going to execute next we got process whoops we got process 100 and process 101 they both want to just open b.txt so in this case they are now independent because they are after the fork so standard rules apply they would each just create a new local file descriptor called one and they would point to a new entry in the global open file table which would have its own position its own flags and its own vnode pointer to a vnode which would point to b.txt and then if we went and we executed process 101 it would open its own file descriptor one which would point to a new entry in the global open file table with its own position its own flags and then whoops its own vnode which points to the exact same file so any questions about that? yep so standard out standard error they would have entries in the global open file table and if I'm typing to my terminal well we saw we could do that ls of command to see what the file descriptor is actually point to so if you're using a terminal file descriptor 0, 1 and 2 all point to a terminal so there's a fake device that looks like a terminal that you can read and write bytes to so whatever you do so because you're fork and then you're all sharing the terminal that's why since they're all sharing this position if you type a character so you type a and hit enter that also means that because they're all sharing the same position only one process is going to be able to read that a you typed otherwise every grand parent would see that a as well if they read from standard in before you and things would get weird so that's also why the standard file descriptors work because while they all point to the same position they multiple processes won't read the same thing because right now if either process reads to do.txt since they're sharing position it'll advance it in both but for both of these they could since they have their own unique entry pointing to b.txt they could both read the entire contents of b.txt because they're not sharing a position alright any questions with that because it's yep yeah so the local ones are just this table here and that's what we call the LOF or local open file table so all they are is just pointers to some entry in the global open file table and their index is the file descriptor you get so the file descriptor is basically just an index into this table so which is why it doesn't actually have to represent a file can represent anything so any more questions about that? alright so here was the answer to that so draw nicer than my chicken scratch writing so hopefully that is more understandable so you have it so now we have to actually store files on an SSD or something like that so we have to figure out a way to store these files and how you store these files is exactly what a file system does so remember SSDs well they kind of behave like memory they have pages so I could represent a file as just a series of pages so how would I store information about the files so for instance if I have to do .txt how would I describe where to go on that disk to actually read the contents of that file so if you were to tell me how to use an array what two things would you need to tell me about the array in order for me to use it yeah the start and how big it is so in this case if I have three files here so maybe I didn't explain that well enough so each of these different colors should represent a different file so if I have contiguous allocation if you wanted to tell me where the green file was you could say well it starts at block zero or page zero so I'll probably use typically when you say blocks you talk about pages on an SSD and it's like a file system related thing so I'll probably use say the term block but it's just probably the same size as a page or slightly bigger so in this case for the green file to describe it I would say it starts at block zero and it's three long well and then if I describe the red file well it's zero one two three four five six so it starts at block six and it is six things long and the blue file starts right after that and it is four blocks long so is there a problem if I do this to represent my files so what would I have to do if I want to make the red file larger yeah yeah so if I assume everything's the same so this is like the beginning of the file and this is the end of the file if I allocate a block backwards I'd have to move everything else anyways so in this case I'm screwed I can't grow it because if I grow it by one block since everything needs to be contiguous in a row I can't grow it easily because it would interfere with the blue file so I would have to move it and make it bigger so is this a great idea if you are constantly making files bigger deleting files and everything like that is this a good way to store files in your file system probably not we probably read and write files a lot of the time if you have to move so say that red file you know was your 50 gigabyte Blu-ray or something like that and well I guess you wouldn't modify it all at a time but say it's my stream recording it's getting bigger and bigger all the time I don't want to keep on moving it and just essentially wasting my SSD and things like that so we need to do better with it than this the system is going to be really fast though because well it's really easy to describe a file everything is all in a row you don't really need much information so just what starting block and the size of it and we also have fast random access because well no matter where I'm trying to access in the file since I know where it starts and say I want to access I don't know byte 10,000 well if I know where byte 0 is and they're all in a row I just start at the beginning and go to byte 10,000 and I can know what block that byte 10,000 is at really easy with just one simple calculation so it's just like the offset block size take the floor of that so if my blocks are like 8 kilobytes well it's probably on block 1 so not on block 0 block 1 so the problem with this is files can't grow easily so they have internal and external fragmentation so that's a new fun term that we will also get into once we talk about memory allocation come up with it here so fragmentation basically just means you are wasting space internal fragmentation means you are wasting space within a block external fragmentation means you are wasting space between blocks so I have internal fragmentation because well if I need an entire block for a file and say they were 8 kilobytes but my file is only 10 bytes I just write hello world or something like that it's 12 bytes well in that case I still have to use an entire block so most of the space is going to be wasted and that's internal fragmentation and then external fragmentation is well when I can't actually use blocks because they are not big enough so in this case if I made the red file bigger by one well I would have a hole of one between the red and the blue but if I never make a file that is only one block big I can never fill that hole and it's going to be wasted forever so that's typically a problem once you come into memory and yeah this is the same problem once we get into memory allocation so like things like malloc would also have to deal with this problem so we can do a bit better so everyone likes link list especially based off lab whatever what was it for everyone likes link list for some reason so what about if we did that for file system so we just do a free list like we had a free list of pages what about to describe a file we just link a bunch of blocks together so in this case if I have the green file well oops I would also save some bytes at the end of each block to point to the next block so in this point if my green file is six blocks large well it could start a block zero and then the index zero block could be this block and then the next block could be this next block could be this and the final block could be this one so pros and cons for this so how do I describe my what data do I need to describe my green file here yeah so if I assume that each block just has a pointer to describe this whole file I just need to know where to start where the head is so that seems to be fairly space efficient and in this case I don't need contiguous blocks at all one is as good as the other so if I want to make this green file bigger I could pick any old block and just point it to that one right so growing files is easy shrinking files is easy in this case because all our blocks are the same so any questions about that part alright what's can anyone guess what is really bad with this part and to give you a hint it has to do with performance yeah yeah so these blocks are pretty big oh yep yeah there's a few things so if I want to go to block 6 or block 4 or something like that I always have to start at the head and keep on going to block 4 that's not good I have to keep on jumping through all the pointers and like you said the pointers are really spread out so one pointer is on one block another pointers on another block which wouldn't be in cache so I'd have to read it we can assume if we're having an SSD reading each block this is fine as any other block they don't have to be sequential but I still have to read every single block every single time I want to access a pointer which would be slow so how would I make that go slightly faster without fixing your issue use a cache I could what about if instead of could I move where I'm storing these pointers to make them closer together yeah I could just put all the pointers on its own block if I really wanted to and just have a gigantic array of pointers so that should speed up things a bit more so that's a good idea and we'll see that next but first you know this is slow random access so space efficient to describe a file I just need to say where the beginning of it is and then the blocks to store pointer the next block in this case the blocks would be slightly smaller but it's probably not a big deal easy to grow and shrink files we have no external fragmentation because well one block is as good as another I can just point to it we still have that internal fragmentation issue where we might not use an entire block worth of storage but in this case our accesses are slow because all our pointers are on individual different blocks so like you said we can just all on a single block put all the pointers closer together and at least we can have slightly better performance and in fact this is the first actual file system we use so all that array of pointers is something called the file allocation table and essentially is that idea of just moving the list to its own block so if you have ever heard of the term fat 32 file system or something like that that's what it stands for file allocation table and it is exactly that and if you are using a windows computer you are using fat 32 because your boot drive must be formatted this way because windows told you so so you are using this if you are using a windows machine so that just as the same idea moves the pointer out of the block and then just it creates a gigantic table of pointers so that everything is closer together and we get a bit of a speed up yep so there would just be a gigantic it would just move all the pointers to just a giant array and that array would just be a giant global array so it is shared between them all so you would have to keep track of what they are pointing to and if they are actually in use or something like this using the exact same thing in my giant array whatever is at index 0 is the pointer of block the next block to block 0 so here block 0 points to block 6 block 6 points to block 2 and same idea as our link list thing so this kind of what you alluded to this is kind of bad because well I need just a bunch of pointers and how big is that array well depends on how big my disk is so if I have a bigger disk that has more blocks I have more elements in this global open file sorry why did I say that more elements in this file allocation table so it just gets bigger and bigger and bigger the bigger your disk is because it is essentially storing all the pointers for it so it is pretty simple and that is why it is used as a drive like it is the file system for booting but you don't really use it in the real world because it is kind of silly and kind of slow and the bigger it is the worse it is so any questions about that one yeah it might use more than one block if it needs if it is that big which is not that great right so the bigger your drive is the bigger this file allocation table is but that is the first one that is actually used and you probably use it without knowing it if you are using a windows machine so has all the same pros and cons of that link allocation but it is a bit more cache friendly so it can actually hold that table in a cache if it wanted to too but the size of that table is going to be linear to the disk size can become really large so is there anything we can do here to further increase random access speed because while this still has to go through pointers and everything like a link list can we do anything better well let's see what we can do index allocation just make it a big array so instead of just having a gigantic table of a gigantic table like a link that represents a link list of blocks I have to follow the blocks why don't I just have essentially a table per file that tells me which block I have to go so in this case for the green file the green file could just have its own array that is as big as however many blocks it is and then it points to exactly what block is being used so in this case block 0 points to block 0 on the disk block 1 of the green file points to this one block 2 of the file points to this one block 3 and now I have nice random access because it is essentially a gigantic array well it is an array that is as big as it needs to be to store the contents of the file so link list is kind of terrible the idea here is to just use an array so any questions about just using an array yeah isn't this bad if I just have one massive file that consumes a whole disk but if I have a massive file I need to keep track of that number of blocks anyways right so what can you do you have to keep track of it somehow otherwise you can just guess and you can't just guess yeah sorry so in this case so I made this red box this is the block that stores a gigantic array and this kind of goes back to our page tables it kind of looks like a page table right like it's pointing instead of pointing to pages it's pointing to blocks so it's kind of the same idea here so in this case if my file is if I have just a block that's storing all of the pointers well it has a limit right it can only store so many pointers if your file is bigger than that you would need another block or what would you need if it was virtual memory and page tables if I want more to address more virtual memory what do I need to do add another level yeah so here same idea that we'll get to later you can add additional levels to this so for this oh yep so as part of the description for the file before we would say what block it starts at if it's like a link list here we could just say what block has the array of pointers so we could describe it by saying exactly where is the red block so if I want to describe file the green file I'll say its array of blocks is at the red block alright so how big could this file be so let's say that this index block just stores pointers to data blocks only there's no other information and say our disk block size is 8 kilobytes and a pointer to a block is 4 bytes so what is the maximum size of a file that can be represented by this index block 2 kilobytes so why 2 kilobytes I'll probably have to go back and forth I'll have 8 kilobyte block 4 byte pointers so in this case if we want to know how many pointers we can fit on a block what do we need to do just yeah just divide them so 8 kilobytes is 2 to the 13 4 bytes is 2 to the 2 2 to the 11 pointers on a single block and if each of our blocks is 8 kilobytes well we could multiply them together to see how big our file could be so in this case if we multiply them together we get 2 to the 24 or in other words 16 megabytes so if your file system could only support files up to 16 megabytes would you be pleased some of you might be but some of you don't watch movies I guess or anything remotely complicated or even have images so in this case probably need to do a bit better so we want to see how big of a file we can support so if we use one block for the pointers we can store 11 pointers and each of those points to a block so we multiply by the block size to see how big our file could be so that's our idea this is file systems more persistence and we'll get into how to improve that later because that will do with our actual file system so just remember pulling for you we're all in this together


What's up everyone? It's your girl Kenzie here from Layton Sports Guards, and I'm ripping a personal for Charles M We've got a 2022 tops chrome formula one racing light box. All righty best of luck Charles Here we go again the light boxes have 16 packs per box looking for the way rave parallels. Good luck. I Didn't get to see obviously I did not stay up till 1 a.m. To watch the F1 race this morning Who ended up winning? Does anyone know? Well to look it up After this if no one knows Here we go Claire. We've got refractor art fagrin pre-max one again She is dudes of these Who came in who was like the top three? You know Charles?  We've got a Liam Lawson refractor on the future stars Liam Lawson and a Lando Norris on the mini diamond McLaren 165 with 299 Loads got a second Nice. I've got our first way rave. It's gonna be a Mick Schumacher for Haas Mick Schumacher Hamilton Latifi There's only one rookie in this this year, and it's a joke on you Fiti Paul D Ocon Alonzo Ocon. We've got green max for Stappin grand pre-winner My heist one there It's gonna be four of 99 nice for Stappin Who's the Hamilton lap-nevin a lap-eleven and never look back? nice Louhan thought he had it Got Louis Hamilton grand pre-winner and a Aston Martin refractor Can y'all not very many people in queue currently we got all over up next with some soccer We know if you have any questions or look up for anything specific We've got future stars on the checkered flag of Bosia look clean Charles I mean I would definitely do some research first. We got Lou ham on the way rave to make sure you know It's worth it. I would look up comps and stuff and see what recent comps are if they're worth worth that Got purple checkered flag of Jack to Han future stars I definitely look at the card first to make sure it's in good condition Yeah, sure thing Like say, you know it costs $20 to slab it whatnot and the card itself Ten or a nine only sells for you know, 40 or 50 bucks I wouldn't George Russell unless it's like a PC card, you know, and you want it slapped up. Absolutely before it Nice Russell there on the way rave Well, but from a profit standpoint, I would definitely look look into comps in that verse Botas on the refractor now if it's like a low number like a gold Lewis Hamilton or something like that or big for stopping I personally would Yeah, that was crazy Charles. Absolutely crazy. Yeah purple a banito for Ferrari like that. That's a card That would definitely slab up to that one is 113 of 399 On so you got Charles Leclerc on the purple and green Ferrari Norris and Ricardo No autos in the light boxes. If you're looking for autostarles, you're gonna have to go hobby And they're not guaranteed in the hobby, but that's where you can hit hit the autos Tee-fee oblin shoe mocker Claire Claren refractor Bestie we've got a max for stopping on the Grand Prix Grand Prix winner Lando Norris refractor speediness. Oh Yeah, that'd be sick might do having a bit sounds good Do Han we've got Liam Lawson refractor on the FT racer Sebastian Vettel speed demons.  All right, that will do for your box there Charles Congrats again on the hits. Thanks so much for hopping in do appreciate your support and we'll get these right out to you


Hello, good afternoon everyone. My name is Nina Chilap and me along with my team are going to present projects under Akash application development group. So, my team consists of first me, Nina, then I have Arun over there and Ajay, Mithali. These are the projects under our group, classroom interaction app which will be given by me and then we have Akash online tech support system extension which will be presented by Amul and then we have analysis of EDX data which will be presented by Pushpug. So, let us start with classroom interaction app. So, what is classroom interaction? Anyone of you, yeah right to make some communication and all. So, what is the exact, what is the problem with that system? Like look at this classroom, it is very huge classroom. If I ask that girl to say, ask a question or say some answer or something, the guy sitting over here will not be able to hear that. It would not be that audible. It may be depending on your power, like if you can speak so loud. So, that is the one problem. So, in IIT Bombay we have mic. So, we can just transfer that mic over there and then she can speak and it will be audible and then there is a problem like it is time consuming like after you this guy ask a question, wants to ask a question. That mic need to be transferred from there to this person. So, it is kind of time consuming. So, we came up with the idea of classroom interaction app. So, what exactly is this app like it is a student teacher interaction in classroom using Akash tablet built in microphone and front camera. So, I will just show you the UI what exactly we are planning. So, first a student need to type his name like she will type is type her name and then a photo will be clicked by front camera and then she will press that center button and it will there will be a server with the server which will connect it to speakers and that server will be with the professor over there. And then after that when you press that button the server will get notification that the person with that name is asking a question. Similarly, there are if there are 10, 15 students each and every one of them can ask at the same time raise the hand we call it at raise your hand. So, person can raise the hand and then there will be a list of all the students over there. So, professor wants that this person should ask the question he will just click on that ok. She should she should ask the question she will get a notification you can start speaking or you can ask a question. So, then she will start and the entire classroom will be able to hear because that server the the tablet will be connected to the server and through via server the speakers are connected. So, everyone will be able to hear and that time each and every each and every tablet at that time will be in a waiting mode. As soon as that will be finished. So, the other person in the queue will get a chance to ask a question and he can even withdraw at any point of time like two person are having same question. So, if that question is been asked the other person ok that question has been solved my doubt has been solved. So, we will just do is just do that you will just cancel the cancel is not ok it is my turn and the her name or his name will be removed from the list automatically. So, this is our app classroom interaction. So, next I will like to call upon Amul to continue the presentation. Good evening each and everyone. First of all the basic idea behind developing a portal on Akash Tech Support is I would like to brief you in some few points. We have distributed around 90,000 tablets all across India. So, taking the queries related to a tablet on the phone is very difficult and tiresome and for that we require a call center. So, we are not here for setting up a call center. So, we thought of developing a portal for Akash Tech Support where queries will be taken from the remote centers all across India. They will register their tablet on the website and they will submit the issues related to a tablet and the queries will be solved through email or through phone call. So, currently we have developed one system rather portal it is a ticket based system. So, the user can register their tablet on the website then a ticket will be generated and their fault will be solved within next 48 hours that is the system we follow here. Then we have on the portal we have put a discussion forum where a student can post the queries can post a solution which we also do not know because tablet is a one of its kind Akash tablet. So, plus auto generated mail. So, once a student you are a faculty register the complaint register the complaint. So, they will get an email on their respective email stating that your query will be solved in next 48 hours plus we have provided FAQs where all the solutions what we have come across we have provided that and the technology behind the portal is currently we are planning to develop more sophisticated portal. So, currently we have used ZUMLA HTML5 PHP and for database we have used MySQL. Now the new features which we are going to put into that portal is SMS service where the person has to register their mobile number with us. So, they will get an SMS stating that your query has been registered with us. So, your query will be solved plus statistical and graphical representation of the faults we have classified around 10 faults in the tablets. So, that has been classified on the website portal. So, according to the fault there will be a graphical representation on the portal plus a new feature of chat application there will be providing a chat application along with the video chat if possible and for that we require technology like Django and Python. I will take you through the web portal. This is the portal we have developed. So, the student has to go on this portal then he has to register the tablet there he has to put his email ID and the tablet ID without tablet ID the portal won't work for him. Once he register his tablet he has to again go on the web portal and login there with the email ID. So, once he logs into the portal he can see FAQs, discussions, submit issues and view issues. In submit issues he has to launch his complaint. See, these are the faults we have identified in the tablet. So, the student has to click on the fault which is facing currently. So, once he clicks on the fault he has to type some text there briefly stating his fault what is facing in the tablet. Once he submit the fault a ticket will be generated then FAQs what I said previously we have provided the questions along with the solution. These are the solutions we have provided then discussion forum right now we don't have any discussion here and there you can see your ticket number date created when you submitted your query and the status and subject and department. That's it from me I will call Pushpuk to continue. Okay, hi everyone my name is Pushpuk. I'm a master student here in computer science and here to talk about edX data analytics. So, edX is an open source MOOC like course developed jointly by IIT Bombay and in edX we collect various kind of data to the user so it can be of the courses, the students data and also the log data which is basically the user behavior. So, edX data analytics is basically to use this data and try to make sense of it. So, can we the challenges can be used to data to determine if two students are copying of each other. If a student is engaging into off-task behavior or trying to game the system. When students give feedback about a particular course can we make more effective sense out of that feedback. So, these are some of the questions that we will try to analyze and try to answer using the data that we collect from edX. But this is more of a research kind of project which is not a software development project. The technology that we use is Hadoop for analyzing big data and we also use Hive and for doing machine learning we use various toolkits such as RapidMiner and WECA.  But you should be good in writing SQL queries because Hive is very similar to SQL and you should have a good background of probability and statistics and any background in machine learning would be great. So, anyone having a background in machine learning or artificial intelligence data mining. So, once you actually join the project we will give you a more detail of what the project actually is. So, who is next?


Everybody welcome back to another Premiere Pro tutorial and this one I'm going to show you how to fix the audio and video not dragging into your timeline. What am I talking about? Let me show you first and I'll show you the fix. So here I've got some footage here and it's got audio on it obviously. And then I've got a second piece here. I'll hit spacebar. It has audio and video as you can see here. Now I'm dragging it onto the timeline but I'm only getting the video. Why is that? It's very simple. The problem is right here. It's called source patching. You either have to have both audio and video on here or neither on in order for this to work. It's the bizarra thing but it is what it is. If you turn them both on for example, now watch when I try to drag this in. It's going to pull in the audio and the video and this also works if you're not getting audio. So if I have just the audio on without the video source patching, I drag and drop it in. I only get the audio. That's the fix guys. Thanks for watching.


Good evening aspirants. Welcome to the Hindu News Analysis brought to you by Shankar Ayes Academy for the day 6th of November 2021. So, these are the list of news articles that I have chosen for today's discussion and they are provided along with the page numbers of different editions. So, when you look at today's articles, we have one editorial and three articles wherein we have a topic on Yamuna and its cleaning project and then we have a brief discussion on the tea tribes of Assam and then we also have a discussion on a study regarding stubble burning and the harmful effects of particulate matter. So, with this brief idea of these articles, come let us get into our news discussion for today. Now, for our next news discussion, I have chosen two articles and these two articles, they talk about the recent Hooch tragedy that has taken place in Bihar. See Hooch means an inferior or illicit alcoholic drink. So, the tragedy here is basically about the consumption of illicit liquor and according to the articles, one of the reasons for this tragedy is the prohibition of liquor in the state. Now, based on this context in this discussion, let us see the background of the incident and then we will discuss about the pros and the cons which are associated with this prohibition. Now, the syllabus covered by this article is highlighted below for your reference. So, first of all, we will see or we will know what is actually happened in Bihar. See, this incident happened in the West Champaran and the Gopalganj districts of Bihar. So, the issue is on the eve of the festival Diwali, it seems that local people, they consumed spurious liquor. See, this spurious liquor contains chemical solvents such as methanol or any other poisonous substances say like that of alum, aluminium chloride and ethyl alcohol and these substances have got the potential to cause harmful or injurious effects to the human body or they can even cause the death of a person. So, spurious liquor is unfit for human consumption and many a times spurious liquor or the methanol is found to be the main reason for causing hooch tragedies and sometimes apart from these, even rectified spirit also results in hooch tragedies and if you are not aware, see this rectified spirit is a highly concentrated form of alcohol which is generally transported for selling as unexized cheap liquor. Now, coming back in this Bihar hooch tragedy, the consumption of the spurious liquid has led to the death of around 25 to 33 people. So, officials in connection with the sale of this spurious liquor have been arrested in this regard. So, this is the background of the article here and it is in this background this particular editorial has been written. So, this editorial basically has raised concerns over the enforcement of prohibition in the state. See, prohibition is nothing but the legal prevention of the manufacture, sale, transportation and the consumption of alcoholic beverages. See, when you take India prohibition of liquor is not something new, it was there right from the 1950's. See, this prohibition of liquor was the result of anti-alcohol protest that took its inspiration from the teachings of Mahatma Gandhi and on that line many states implemented prohibition by 1950's and such states which implemented prohibition were called as dry states. Now, say for example Gujarat has had a total alcohol ban since 1960 and hence it is called a dry state but then many states later withdrew their prohibition. Now, in the case of Bihar, complete prohibition is being implemented since April 2016 and according to the author Hooch tragedies are an unintended but an expected consequence of this total prohibition. So, now let us move on to see the various pros and the cons which are associated with this prohibition or ban on alcohol. So, first let us start with the positives associated with it. See, firstly alcohol affects public health. So, in this slide this particular ban helps in maintaining the health of the public. Secondly, the ban has got certain economic and social consequences because generally men who consume alcohol they tend to spend all their money for buying liquor rather than on spending on essentials. So, this obviously affects the women and the children of the family ultimately pushing them into poverty. So therefore, when liquor is banned it actually helps or supports the women. So, this is one of the reasons why prohibition is supported by most women and apart from this it also safeguards the families from the social level because it increases the household expenditure on basic goods related to food and education. So, now let us move on to see the various negatives or the cons which are associated with this total prohibition. So, the first and foremost is it affects states finances. See, alcohol is a state subject and our constitution empowers the states to levy excise duties on alcoholic liquors for the purpose of human consumption that are manufactured in the state. So, that means the revenue for the state is affected due to total prohibition and this loss of revenue is one of the main reasons for lifting of prohibition in many states. And secondly, the prohibition raises the question of individual freedom. And thirdly, this prohibition leads to the spread of bootlegging industry which are run by liquor mafias which eventually leads to a parallel bootlegging economy. See, bootlegging means the illegal manufacture distribution or the sale of alcohol and if you closely analyse this bootlegging is a reason for the manufacture of poor quality or spurious liquid which leads to the death of many. And this bootlegged illicit liquor is also illegally smuggled to be sold across states. So, in short prohibition leads to unregulated production and also the sale of liquor via the black market. And this leads to excessive consumption of illicit alcohol and it also encourages other forms of intoxicating abuse say like that of drug abuse. So, this shows that the total prohibition does not solve the problem of alcoholism and addiction. And most importantly, a simple prohibition without proper implementation does not stop the sale and consumption of alcohol. Apart from all these, the total prohibition also affects the tourism industry because tourists cannot consume alcohol even for recreational purposes if they are totally prohibited. So, these are the negatives of a total prohibition. So, to conclude according to the author the weaknesses of institutions implementing the prohibition should be addressed and along with this vigorous campaign against alcoholism and also in setting up of de-addiction centres in every district will actually help in reducing these future hooch tragedies in the longer run. So, these are the important points from these two articles. Now, with this learnt points in mind, come let us get into our next news discussion. Now, let us take up this news article. So, the news here is that the Assam cabinet has approved the reservation of seats in the state run medical colleges for the students from the Tea Tribes community. So, this is the news here. Now, based on this context let us learn some important fact about the Tea Tribes community of Assam who are in limelight here. See, as per the information made available by the National Commission for Backward Classes there is no single community described as Tea Tribe in the central list of OBCs for the state of Assam. So, to put it simple, the term Tea Tribe is a broad term which is used to refer to those people who are associated with the tea industries of Assam. So, historically the Tea Tribes, they migrated to the mainland of Assam prior to the Indian independence and their migration can be traced back to the period of the British Raj when the colonialists started to exploit the economical potential of the region through tea plantations in the early 1820s. And another major reason is Assam which was known for its tea industries had a lot of plantation work which demanded significant human power. So, for this reason the Tea Tribes were brought in as indentured labourers from various provinces of India and Assam has got around 1000 tea estates where people originally from Orissa, Madhya Pradesh, Bihar, Andhra Pradesh and West Bengal have taken up employment. And since then they have made Assam their permanent home and during their tenure at the plantation work the communities they eventually began to be identified as Tea Tribes. So, this is how the Tea Tribes formed. Know that among the Tea Tribes itself there are communities of Tea Tribes known as the X Tea Garden Tribes and these X Tea Garden Tribes is a term which is used to refer to those members of the Tea Tribes who have settled down close to the tea estates in the state after the end of their contract and they occasionally provide their services as casual labourers. Note that there are as many as 96 castes in the central list of OBCs for the state of Assam who are falling under the description of Tea and X Tea Garden Tribes and these people they not only constitute a sizeable chunk of the population in the state but they also play a major role in the tea production in the state and in fact about 53% of the total tea production of the country is produced by this community and this contributes to the economy of the state as well. And on talking about the distribution see people belonging to the Tea Tribes communities cannot be limited to certain areas. In the sense they are spread all over the entire state of Assam and economically these people are quite backward and these communities they also have extremely low literacy levels. So due to these reasons steps have been taken by the government for improving the level of literacy and education of these people and apart from these even other economic support are being given for generating their family income under the state plan. And note that since 1983 to 1984 the government of Assam has been implementing various welfare initiatives through a separate directorate called the Directorate for Welfare of Tea and X Tea Garden Tribes of Assam. In order to accomplish the socio-economic development of the Tea Tribes people and in 2004 the government of Assam established the Tea Tribes Welfare Department also as a separate administrative department. And on that line now as mentioned in today's article the Assam cabinet has also approved the reservation of seats in the state and medical colleges for the students from the Tea Tribes community. So these are some of the important facts about the Tea Tribes of Assam. Having these points in mind let us move into our next discussion. Now for our next news discussion I have chosen this article which is basically about water pollution and to be precise about the pollution in river Yamuna. See river Yamuna which was once regarded as the city's lifeline is now deteriorating and its pollution level is said to rise as the river enters deeper into the national capital. And as per this article river Yamuna is found to carry fecal coliform or in other words microbes from human and animal excreta beyond the limits which is permitted and this pollution of fecal coliform is found at all sites except the Palla village where it enters Delhi. So one of the major causes of pollution in Yamuna is the 22 drains which damp the sewage and also the industrial effluents into the river. And apart from this illegal industries has also got a role to play in the amount of pollution that ends up in the river. So at such a juncture the role of sewage treatment plants becomes really important in depolluting the river Yamuna which is in a contaminated stage and on that line this particular article talks about the sewage treatment plant that is adopted to clean the river and it further goes in deep and it explains the various stages that is involved in this cleaning process. So this is the ultimate crux of this article here. So with this idea in mind come let us approach this discussion. The syllabus covered by this article is given below for your reference. So first let us start our discussion with a brief understanding about river Yamuna. See the river Yamuna is a major tributary of river Ganges and it is the second largest tributary river of the Ganges and the longest tributary in India. And this river Yamuna it originates from the Yamunotri glacier which is near the Bandarpunj peak or the Bandarpunj peak in the Mussoori range of the lower Himalayas. And there it originates at an elevation of about 6,387 meters above the mean sea level in the district of Uttarakshi which is actually the town in Uttarakanta. So that means Yamunotri which is located to the north of Haridwar in the Himalayan mountains is the source of this river Yamuna which is in libelite at today's article. So from there it travels a total length of around 1376 kilometers before it merges with the Ganga at Triveni Sangam or at Prayagin Allahabad. So basically this river traverses through the states of Himachal Pradesh, Uttar Pradesh, Uttaranshal, Haryana, Madhya Pradesh, Rajasthan and the national capital territory Delhi till it is confluence with Ganga. So this is the path it flows through. Remember the stretch of the river from its origin to Hockla near Delhi is called as the Upper Yamuna and some of the important tributaries of the Yamuna river are Tones, Chambal, Hindon, Betwa and Ken. And apart from this other smaller tributaries of the river are the Girri, Sindh, Uttangan, Senkar and the Rind. So these are some important facts that we need to have in mind whenever we learn about river Yamuna. So with this basic understanding now let us move on to see the intensity of water pollution in this particular river. See as we already saw river Yamuna has got a large basin which covers like around 6 states and also the national capital territory of Delhi. So due to its large basin the river water acts as a lifeline for many thousands of people and it is used for multiple purposes say from irrigations to industrial reasons. So due to these factors the river water has been subjected to extreme pollution both in terms of quality as well as in terms of quantity. See the river is polluted by both point as well as non-point sources. See those pollutions that originates from a single identifiable source say like that of a discharged pipe from a factory or a sewage plant is called as a point source pollution. So just remember that a point source pollution is a pollution which is caused by a single identifiable source. So when you take non-point source pollution it is the opposite of point source pollution and a non-point source pollution is a pollution that does not originate from a single source or a single point and it has got various sources. So as I told you this Yamuna river is polluted by both point sources as well as non-point sources and among these the National Capital Territory Delhi is the major contributor and followed by that comes Agra and Mathura. So approximately around 85% of the total pollution is said to be from the domestic sources and this condition is further found deteriorate due to significant water abstraction. See water abstraction is nothing but the extensive water with royals which ultimately reduces the dilution capacity of the water or the river in this case. So one example of this water abstraction is the natural source of water and the natural source of the natural source can be a river or a lake or a spring or stream or a aquifier or any other natural source for that matter. So water abstraction is the case. So one example of this condition is the stretch between the Vazirabad Baraj and the Chambal river confluence and this particular stretch is said to be critically polluted and another example for such an intense pollution is the Delhi stretch of 22 km of this river and as per the data this is said to be the most polluted place among all others. So on looking at the important role that is played by this river and the lives of the people involved we can understand that it is really important to conserve this river and also to maintain its quality as well as its quantity and this is where the sewage treatment plants have come into play. So by now we have a brief understanding about river Yamuna and the intensity of the pollution therein. So now let us briefly see how the sewage treatment plant which is adopted to clean this river Yamuna actually works. See this process involves two stages. The first is said to be the primary stage and the next comes the secondary stage. See usually there will be a storm water drain which is designed to transport the rain water to a water body. Now apart from this storm water drain there will also be a separate sewage network which is not connected to the storm water drains and the sewage which is collected from this network will be treated at the sewage treatment plants. But then what happens in the case of Delhi is that the sewage gets discharged into storm water drains at several locations. So obviously this leads to the rain water getting mixed up with the sewage which ultimately leads to the pollution of water. So due to this reason in most situations the sewage treatment plants they take water directly from the sewers they clean it and they either reuse it for purposes other than drinking or they return it to the drains where it runs into the Yamuna. So now let us briefly see the different stages of the water treatment that is involved here. So in the primary stage the water is passed through a coarse filter which is located at the tunnels entrance and the big floating trash which are present in the water at the initial stages are collected at this first stage and though the big floating trashes are collected still a lot of smaller floating particles in the water remains. So next this water is made to flow to a storage sump which is present inside the plant and this water is then pumped up to a large overhead tank from where it flows through various chambers. So then the water is made to travel through two screens. So the one is a medium screen that traps all waste pieces which are larger than 2 millimetre and the other is a fine screen that traps all waste bits which are larger than 5 millimetre and even after these stages the water is still blackish and also stinky at this point. So in the next step the water is made to pass into a grid chamber which is actually another tank where avia particles settle down due to gravity and finally the water is made to pass through an aeration chamber where in grease, oil and other contaminants are removed from the water by mixing it with air and all the collected contaminants are then kept in a separate chamber. Now comes the secondary stage. So by now all the heavy particles are removed from the water. So that means any pollutants that are existing in the water at this stage are either dissolved or they are suspended in it. See the suspended particles are nothing but the microscopic pollutants that float in the water. So as I told you they are suspended right. So to be removed they must be made heavy in order to sink to the bottom. So in order to achieve this or in order to make them heavy in order to make them sink at the bottom ferric alum is first added to the water in one chamber and followed by this the addition of polyelectrolyte is made in another. So in this process the avia particles settle down due to gravity and at this point the biological oxygen demand of the water is reduced to 75% and also the color of the water improves. See this term biological oxygen demand is nothing but the amount of dissolved oxygen which are consumed by microorganisms to decompose organic matter present in the water. So a higher value of this biological oxygen demand implies that the water quality is too low or it implies lower quality of water. So the avia particles which are removed from the water they form a sludge and they then transferred into another tank and there it is filtered to remove any extra water before it is made to fall through a pipe from the top into a dumper and this sludge is later used in landfills. See after the suspended particles are removed only dissolved particles are left in the water. So to remove these dissolved particles the water is fed to aeration tanks which contain bacteria that eat the dissolved particles and are fed with air and then the water is made to flow into another tank where a different type of bacteria eats up the ammonia which is present in the water. So by enough the biological oxygen demand value of the water at the end of the process is around 6.47 milligram per litre and this is actually better than the limit which is prescribed by the National Green Tribunal and if you are not aware remember NJT has recommended or fixed the standard to be at 10 milligram per litre and the water which is clean in this process is around 6.47 milligram per litre which is actually better than the limit prescribed by NJT. So the cleaned water is then supplied to the Prakati Power Corporation Limited wherein it is used for power generation. So this is the overall framework on how this sewage water treatment happens in Delhi or how the pollution in the Amunah River is being controlled at present. See according to the Delhi Pollution Control Committee around 22 of the total 33 sewage treatment plants in the city fail to meet their demands and this is where the issue arises. See if you remember at the beginning I told you that around 14% of all sewage generated in the city is currently not being treated and one major reason for this is the shortage of infrastructure. See what happens is at some sewage treatment plants the biological oxygen demand of water following the process is found to be more than 10 milligram per litre. So to reduce this biological oxygen demand further to limit below 10 milligram per litre we need more tanks for various procedures and this is where the problem happens because many sewage treatment plants they do not have the adequate space for additional development and this particular article here highlights this important matter of concern. So these are the important take away points from this particular article. So to conclude in this article we had a brief understanding about River Yamuna its major tributaries and also we saw about the intensity of water pollution that is happening in River Yamuna and we also saw about the various reasons for the river water to get polluted and then towards the end we saw about the sewage treatment plant which is currently at practice in depolluting the river and we also saw the various stages that are involved in this process. So with these learned points in mind come let us move into our next news discussion. Now our next news discussion is going to be based on this news article. So the news article here mentions about a study which is related to the stubble burning effect on the air quality of Delhi. So this study has been conducted by the Energy and Resource Institute and it has been supported by the Central Pollution Control Board. So basically the study aims to analyse whether stubble burning near residential areas adversely affect the respiratory health of people present there. So on that line the study has measured and it has compared the air quality monitoring and the respiratory health parameters during different exposure periods and so for this purpose the study has quantified fine particulates pollution. See here the term fine particulates are nothing but the particulate matter 2.5. First of all remember that stubble burning means the burning of crop debris and residues. So it is also called as a crop residue burning and this crop residue burning is actually a huge contributor of fine particles in the Delhi and the NCR region during the winter season every year. So you may wonder why this fine particulates pollution are taken into account. So to know the reason behind this you should first know what is a particulate matter. See particulate matter is the term which is used for a mixture of solid particles and liquid droplets that are found in the air. See among the particles which are found in the air some particles are so small that they can only be detected using an electron microscope and these are the particulate matter 2.5. See this particulate matter 2.5 are particles with diameters that are generally 2.5 micrometers and smaller than that. That is it is even 30 times smaller than a single strand of air. Remember these particles are so fine that they are easily inhalable and since they are inhalable particles they pose a higher health risk to the public especially it is of higher risk to the farmers who are living in the crop residue burning and nearby areas. So as I told you particulate matter 2.5 are inhalable particles so that means these particles can enter into our lungs and when they enter into our lungs they get settled on the inner lining of the alveoli. So this shows that even a short term exposure can actually damage the lung function and it can also exacerbate asthma and other heart diseases and unfortunately long time exposure to such particulate matter is associated with an increased rate of chronic bronchitis, reduced lung function and also an increased mortality from lung cancer and heart disease. So by now I hope you have a basic understanding of the particulate matter and also why they are considered to be a pollutant and their harmful effects as well. So now let us move on to see the findings of the study. See firstly the study is found that the concentrations of these particulate matter 2.5 is found to be increased almost 4 times when compared to the standards that were set by the central pollution control board. And if you are not aware the central pollution control board has set the ambient air quality standard for the particulate matter 2.5 to be 60 micro grams per cubic meter. But then during the crop residue burning period the presence of the particulate matter 2.5 in the ambient air is found to be around 193 to around 270 micro grams per cubic meter which is actually way higher than that which is prescribed by the central pollution control board. Secondly the study has provided insights regarding the stubble management interventions and it was found that all the study regions had similar exposure to particulate matter 2.5. So this means that it did not matter whether the regions implemented the interventions fully or partially or did not use any intervention. Still the exposure was found to be same because the regions are closely clustered. Thirdly during the crop residue burning there were evidences of around 2 to 3 fold increase in the respiratory symptoms along with skin rashes, runny nose or itches of eyes etc. And this could be witnessed across all age groups say right from 10 years to about 60 years of age and particularly the highest number of respiratory complaints were found to be reported by the elderly people. But the highest decline in the lung function was seen in the youngest age group who were between the age group of 10 to 18 years. And then if we consider the gender then the adverse effect of the crop residue burning on the lung function was found to be more pronounced in females than in males. So to conclude the study has found a strong association between the exposure to particulate matter 2.5 which is caused due to the crop residue burning and the poor respiratory health in the farming communities. And these are the important points that we need to know from this article. So having done with our article discussion for today let us now move on to the next segment of our in the news analysis which is going to be the practice question discussion. Now look at this question in the constitution of India prohibition of the consumption of intoxicating drinks and drugs is included in option A the preamble to the constitution option B directive principles of state policy option C fundamental duties and option D ninth schedule. See the right answer here is option B that is the directive principles of state policy to put it more clear see under article 47 of the directive principles of state policy the constitution of India envisages that every state shall endeavor to bring about the prohibition of the consumption except for medicinal purposes of intoxicating drinks and of drugs which are injurious to health. So therefore the right answer here is option B that is directive principles of state policy. Now moving on to the next question look at this question consider the following statements regarding particulate matter statement one these are the small particles which are smaller than a single strand of air statement two they can only be detected using an electron microscope and cannot be seen with the naked eye so which of the statements given above is or are correct see you should be really careful while reading the statements see particulate matter as I told you earlier in our discussion is the term which is used for a mixture of solid particles and liquid droplets which are found in the air so some particles such as dust dirt smoke are generally large or dark enough to be seen with the naked eyes but then there are also certain particles which are so small that they can be detected only using an electron microscope so this shows that the second statement is incorrect because it is said that they can only be detected using an electron microscope and cannot be seen with the naked eye now coming to the first statement see this particulate matter includes two sizes of particles one is the particulate matter 10 another one is the particulate matter 2.5 so when you take the particulate matter 10 they are actually inhalable particles with diameters that are generally 10 micro meters and smaller and when you take the case of particulate matter 2.5 they are actually fine inhalable particles with diameters that are generally 2.5 micro meters and smaller and among these two that is among the particulate matter 10 and particulate matter 2.5 it is the particulate matter 2.5 which is 30 times smaller than a single strand of air so this makes the first statement also incorrect see if you closely analyze you can find that the question is about particulate matter but then the statements are about the particulate matter 2.5 in particular and they do not apply to particulate matter 10 so since both the statements which are given here are incorrect the correct answer here will be option D that is neither 1 nor 2 now coming to this question the world's largest riverine island Majuli is located at which of the following states so the right answer here is option A that is a sum so for those who are not aware about Majuli I'll give you a very brief introduction or a description about it see riverine island is also known as river island and the word riverine means anything that is related to rivers so that means islands which gets formed in the river when the water level drops down is called as riverine islands so these types of islands are also created when two rivers interconnect with each other so many islands which have formed in the Bangladesh by the Brahmabutra are some of the examples of riverine islands and another good example for riverine island is the Majuli which is an Assam so it is basically an island in the Brahmabutra river and in 2016 it became the first island to be made a district in India so just remember this point that the world's largest riverine island is Majuli and it is located in Assam and also remember that in the year 2016 it became the first island to be made as a district in India so coming to the last question for the day consider the following pairs so in one side you have the rivers and then in the other side you have the names so this question is actually based on Panch Prayag or the five confluence which is the holiest of the confluence after the Prayag in Prayagraj so let's not go deeper into that if you could remember during a discussion about the origin of river Ammona I mentioned that it originates from the Ammonotri glacier near Bandarpunj peak in the Musuri range of the lower Himalayas and I also said that Yamunotri which is located to the north of Haridwar in the Himalayan mountains is the source of the Yamuna and from there I say that it will travel a total length of around 1376 kilometers before merging with the Ganga at Triveni Sangam or Prayagat Alhabath so have this idea in mind now having this idea look at this question it is given about the confluence of Alaknanda and Dawli Ganga and the confluence of Alaknanda and Nandakini and the confluence of Ganga, Yamuna and Saraswati so if you could recall the point I told you that the river Yamuna travels a total length of around 1376 kilometers before merging with the Ganga at Triveni Sangam so and when you look at the third statement here you can clearly see that this point is reflected here that is it is said that the confluence of Ganga, Yamuna and Saraswati is Triveni Sangam so just with the words Ganga, Yamuna and Triveni Sangam we can actually guess that this is a correct statement so by guessing that when you look at the options given you can find that the third option is only given in option D because in the first three options the third statement is not given so according to our guessing the third statement is right only option D has got the third statement we can go with the third statement which is actually the right answer here that is the confluence of Ganga, Yamuna and Saraswati is the Triveni Sangam and so the right answer here will be option D that is 1, 2 and 3 so with this we have come to the end of today's inter-news analysis and if you had liked our video then don't forget to like, comment and share and do subscribe to Shankar Ayes Academy YouTube channel for more updates regarding UPSC Civil Services preparation.