Below is a list of most comfortable airline seats for flights to/from India compiled from seatguru.com .. 

Seat Pitch is the distance from any point on one seat to the exact same point on the seat in front or behind it. While it is not the exact equivalent of "legroom", it does give a very good approximation of how much seat room you should expect. Bottom line: the more seat pitch the better.

Seat Width is typically the distance between armrests on a seat. If there is no armrest, the seat cushion is assumed to be the seat width. Bottom line: the more seat width the better.

1. Air India - pitch - 34.0"  width - 18.0"  with 126 degree recline 

2. Singapore airlines - pitch - 32.0" width - 19.0"

3. Qatar airlines - pitch - 32.0" width - 18.9"

2. Jet Airways - pitch - 32.0" width - 18.5" with netted footrest

3. Emirates - pitch - 32.0" width - 18.0" with 6 inch recline

4. Continental - pitch - 31.0" width - 18.3" with 5 inch recline

5. Cathay Pacific - pitch - 32.0" width - 17.5"

5. Air france - pitch - 32.0" width - 17.5"

6. Lufthansa - pitch - 31.0" width - 17.5" with 113 degree recline

7. British Airways - pitch - 31.0" width - 17.5"

8. Delta - pitch 31.0" width - 17"