Indira Gandhi airport terminal 1 I think is the best domestic airports in INDIA as compared to Mumbai, Kand Lucknow airports.
The best part of this is that it provide all services under a same shelter for instance: a big shopping mall at one side, food court at one side, departmental store at other side.
I mean its just awesome.A full tight security for 24* 7 hours people feel very secure here and people who are working there are very cooperative