Why is there a 30 minute time difference between New delhi and the rest of world?

There is no 30 minute time difference between New Delhi and the rest of the world. New Delhi is located in the Indian Standard Time (IST) zone, which is UTC+05:30. This means that New Delhi is 5 hours and 30 minutes ahead of Coordinated Universal Time (UTC), which is the basis for most time zones in the world.