Question

Why there is time difference between the northern and the southern extremes of India?

Answer 1

The western India longitude is 68 degree and 98 degree is on the eastern boundary so their is a difference of total of 1 hour per 15 degree of longitude is the two extremes differ by 2 hours. So when the sun set at 4 pm in Kohima than than the sun sets in Porbunder by 6 pm.  IST was fixed in 1906 midway at 82.5 degree or 5 per hour ahead of GMT.  So their is a demand from northeast region for a seperate time zones. 

Answer 2

The time is very important part of our daily lifestyle.We use GMT method to calculate the different local times of different locations on the earth.

The latitudinal distance difference also causes local time difference according to this GMT theory.

And the Northern and Southern extremes of the India are situated in a significant amount of latitudinal distance, that's why the local times of the northern and southern extremes of the India are different from each other.