Question

what is the requirement of a standard time for india and how is ot calculated​

Answer 1

• In military and aviation time IST is designated E* ("Echo-Star"). Indian Standard Time is calculated on the basis of 82.5°E longitude in the city of Mirzapur, Uttar Pradesh, which is situated approximately on the corresponding longitude reference line.

Answer 2

Earth rotates 360° in 24 hours means 1 degree in 4 mins. Internationally longitude is set 0 at Greenwich if you move towards usa time will be negative and positive while moving towards East…as sunrises from east..you know…means for every degree shift in longitude towards india you add 4 mins starting from Greenwich and indian standard time is measured at 82.5 longitude…that means 82.5 * 4 = 330 which is 5 hours 30 mins..hope it helps :)