Originally Posted by Yaatri

The number of miles/points you get depends on routing and the class of your ticket. By class, I don't mean simply economy or business or first. In some programs the number of miles also depend on the fare basis.
You can maximise your miles by taking a circuitous route pprovided the cost does not go up too much.

As it has already been pointed out two RT's between DEL and NYC will get you about 30,000 miles, if you travel in a class that will award you 100% of the miles. In some programmes, miles expire. Unless you have plans to use your miles, miles will be credited to your account and then dropped off as they expire. At 30K miles a year, you can get silver status, which does not get you much these days.

IMO you should join an airline that's a member of star alliance. Air India is not already in star alliance. Star alliance gives you lots of choices to travel to India. LH, TG,SQ, LX,AC,CO,SA,SK,SN,TK,OS and BD are some of the airlines that serve Delhi.