Question

Why is the standard time of india has been decided by the local time at 82.5 degree east longitude?

Answer 1

From Gujarat to Arunachal Pradesh there is a time lag of two hours. Hence, time along the Standard Meridian of India (82° 30' E) passing through Mirzapur (in Uttar Pradesh) is taken as the standard time for the whole country.

Answer 2

82.5 divides india into two halfs.Moreover having different time zones in a single country like india would give way to confusions . therefore a single longitude is taken.