When the east‒west stretch of a country is vast, it creates confusion due to variation in time in the same country. Difrent parts of the same country actually has diffent time ast the same point.This confusion results in the need for a standard time to maintain a uniformity throughout the country. Since the longitudinal extent of India is almost 30 degrees, India has adopted 82.5o longitude, which is in the middle, as the measure for calculating standard time of the country.