General Knowledge - Indian Geography - Discussion

No its 5.5 times ahead of GMT. So none of the above.

Can Anyone tell me how to Calculate it?

The longitude against which Indian Standard time is set passes through Allahabad, India.

British India did not adopt the international standard time zones until 1905 when the meridian passing through Allahabad at 82.5 degree east (of Greenwich Meridian) longitude was picked as the central meridian for India, corresponding to a single time zone for the country at 5 hours and 30 minutes in advance of GMT.

This went into force on January 1, 1906. However, Calcutta time was officially maintained as a separate time zone until 1948. Bombay time was maintained but only informally until about 1955.

After independence and the partition of British India, Pakistan stayed on Indian Standard Time for three years and adopted Pakistan Standard Time at 5 hours in advance of GMT in 1951.

ARVIND, its correct. When it is noon IST at Allahabad in India, the time at Greenwich, London, will be 0630 because its 5. 5 times ahead of GMT.

0630+0530=12.

If noon at Greenwich then 1730 in India.

Guys here is a simple rule.

When we go towards west then the time decrease and when we go towards east then time increases. So IST is ahead of 0 degree longitude, so to reach the Greenwich time we will have to go towards west so :- 12-5.30 = 6:30.

If we go from west to east we will add 4 min to every 1 degree, so 82.5*4 = 330/60 = 5.5 hr.

Therefore 12-5.5 = 6.30 hr.

If it is 82.5° of GMT then it should be noon i.e. 12 plus 5.30 equal 17.30 hours.

IST is 5.5 hr forward in summer and 4.5 hr forward in winter as compare to GMT.

If 12 pm here then 6:30 am in GMT in summer and 7:30 am in winter.

Please explain it in more simple way.

Consider 12:00 noon - 5.30 hrs = 6:30 am at greenwich. @Anup gowda is correct.