Indian Time Zones (IST)
India Time Zones
India's Time Zones were established in 1884. Originally there were two Time Zones, the Bombay Time and Calcutta Time.
Bombay continued to have a different time (39 minutes behind IST) until 1955.
IST, which is GMT plus 5.30 hrs, came into existence in 1905.
In certain time-zone maps, IST is also designated E*. There is only one time
zone for all of India. India does not observe any form of daylight saving time
or any other seasonal adjustments to the time.
India does not observe Daylight Saving Time now. During the Sino-Indian War in 1962 and the India-Pakistan Wars in 1965 and 1971, it was used.
With India's western and eastern borders some 2,000 km (1,250 miles) apart, India could well have three time zones! Like China, however, India chooses to have a single time zone across the whole country.
Railway Time or Madras Time
In the very early days of railways in India, local time was observed at each large city, in common with practice in most other countries at the time. Because of their importance as commercial and economic centres, Bombay time and Calcutta time assumed special importance and were followed for many official purposes in the late 19th century (Bombay Time from 1884), effectively forming two time zones for British India.
Calcutta time was 5 hours, 30 minutes, and 21 seconds in advance of GMT, while Bombay Time was 4 hours and 51 minutes ahead of GMT.
Many railway companies, however, standardized on using Madras time as being in between Bombay and Calcutta times, and often this, rather than Bombay time, was used in Indian timetables from the late 1880s onward.