what is meant by indian standard time?what is itsimportance?
The longitudanalextent is 30 degree.The sun rises in the east and sets in the west.It takes 4min. for the sun to move across 1longitude thus the eastern most point of india would be 2hr ahead of the western most point in accordance with the local time.So to avoid confusion in the airand rail timings,conference etc. a standard time is observed all over the country.the standard meridian of india is 82 degree 30 east....
hope this helps ya lakshya..........
Indian Standard Time (IST) represents the time observed throughout India, with a time offset of UTC+5:30. India opted out of observing daylight saving time, (DST) or other seasonal adjustments, although briefly using DST during the Sino–Indian War of 1962 and the Indo–Pakistani Wars of 1965 and 1971.  In military and aviation time, E* ("Echo-Star") designates IST. 
Indian Standard Time calculates on the basis of 82.5° E longitude, just west of the town of Mirzapur, near Allahabad in the state of Uttar Pradesh. The longitude difference between Mirzapur and the United Kingdom 's Royal Observatory at Greenwich translates to an exact time difference of 5 hours 30 minutes. A clock tower at the Allahabad Observatory ( 25.15° N 82.5° E ) calculates local time, though the National Physical Laboratory, in New Delhi has been entrusted with the official time-keeping devices. 
if it is help ful pls give me athump up
the indian standard time is the time observed by the whole country.the standard meridian of india is 82 degree 30 min east is taked as standared time
The main importance of standard time is that it helps in organising a uniform schedule for transport like railways and airways. It cuts down on costs that would be otherwise incurred on adjusting to different time schedules and the subsequent loss of time. It also enhances economic productivity across the country by helping to coordinate economic activities