Question

why it is necessary to have stander time​

Answer 1

Answer:

The time of a place depends on the longitude that passes through it. ... Since many meridians pass through it, it is important to adopt the local time of one central meridian of a country as the standard time for the country. Thus, we need a standard meridian for the country.

Answer 2

Because longitudinal time from one end to other may vary so the middle passing longitude is considered as standard meridian