Time in India

For most of India's history, ruling kingdoms kept their own local time, typically using the Hindu calendar in both lunar and solar units.

[6] For example, the Jantar Mantar observatory built by Maharaja Sawai Jai Singh in Jaipur in 1733 contains large sundials, up to 27 m (90 ft) high, which were used to accurately determine the local time.

Indian Standard Time came into force on 1 January 1906, and also applied to Sri Lanka (then Ceylon).

[8] In 2014 Assamese politicians proposed following a daylight-saving schedule that would be ahead of IST by an hour, but as of March 2020 it has not been approved by the central government.

[12] Plantations Labour Act of 1951 allows the union and state governments to define and set the local time for particular industrial areas.

India and the Indian subcontinent observed "daylight saving (DST)" during the Second World War, from 1942 to 1945.