The standard meridian of India is 82.5 degrees east of the Greenwich Meridian. This meridian passes through the city of Allahabad. It runs through the center of the country.
In 1905, this longitude was selected as the meridian to create the Indian Standard Time. In winter, the Indian Standard Time is 5 hours 30 minutes ahead of Greenwich Mean Time. In summer, this time difference is 4 hours and 30 minutes due to adjustments made for daylight savings time. India does not use daylight savings time.
After India became independent in August 1947, there were three separate time zones in India until 1955. As of 2014, the whole of India follows the time set on 82.5 degrees east.