Calcutta Time
Calcutta Time was one of the two official time zones established in British India in 1884. It was established during the International Meridian Conference held at Washington, D.C. in the United States. It was decided that India had two time zones: Calcutta (now Kolkata) would use the 90th meridian east and Bombay (now Mumbai) the 75th meridian east. It was determined as 5 hours, 53 minutes and 20 seconds ahead of Greenwich Mean Time (UTC+5:53:20). Calcutta Time was described as being 23 minutes and 20 second ahead of Indian standard time and one hour, two minutes and 20 seconds ahead of Bombay Time.