Bloomberg has an excellent global economic calendar which mostly covers US and UK events.

Click Here to checkout Bloomberg global economic calendar.

For Indian Markets, there's not much good info on it.
However, ICICIDIRECT has a decent event calendar in their Market Overview Page.

Click Here to checkout Indian Stock Market Calendar

I basically look for important events in a month like RBI Policy, Inflation Data, IIP and so on.
This is pretty useful for traders to hedge during important economic events.