Indian Standard Time (IST), sometimes also called India Standard Time, is the time zone observed throughout the Republic of India, with a time offset of UTC+05:30. India does not observe daylight saving time or other seasonal adjustments. In military and aviation time, IST is designated E* ("Echo-Star"). It is indicated as Asia/Kolkata in the IANA time zone database.
The Indian Standard Time was adopted on 1 January 1906 during the British era with the phasing out of its precursor Madras Time (Railway Time), and after Independence in 1947, the Union government established IST as the official time for the whole country, although Kolkata and Mumbai retained their own local time (known as Calcutta Time and Bombay Time) until 1948 and 1955, respectively. The Central observatory was moved from Madras to a location at Shankargarh Fort in Allahabad district, so that it would be as close to UTC+05:30 as possible.
Daylight Saving Time (DST) was used briefly during the China–India War of 1962 and the Indo-Pakistani Wars of 1965 and 1971.