The fares for resident indians and foreigners resident in India are lower than the so called US$ fares for non-resident indians and foreigners.

If you purchase a cheaper indian ticket, you maybe asked for a proof or residency by an overzealous airline agent. If you can't show that, you will be asked to cough up the fare difference.

The same applies for hotels. Do the trick only if you are willing to take the risk.