So far, the world has been able to cope with such demands as the scene of urbanisation has shifted from one region to another and the overall magnitude of increase in urban population has been manageable.
What is new in the next 25 to 30 years is that three of the world's most populous countries, China, India and Indonesia, with combined total population of about 2.5 billion will be undergoing this process simultaneously, with Pakistan and Bangladesh not much far behind.