Multiple choice general knowledge What is the difference between Indian Standard Time and Greenwich Mean Time? 6: 30 hours 6 hours 5: 30 hours 5 hours Reveal answer Fill a bubble to check yourself C Correct answer Explanation Indian Standard Time (IST) is 5 hours 30 minutes ahead of Greenwich Mean Time (GMT). India is at 82.5°E longitude, which is 5.5 hours ahead of the Prime Meridian (0°). IST does not observe daylight saving time.