Hi, I got my Airtel SIM card at the internaional airport like adviced, no problem there.I suspect I could have gotten away even without the ID photos but the lady at the counter caught sight of the stack of photos I had in the purse so I was 1 shoot poorer.In all, I had to submit
a) proof of residency ( apparently, the address would be best from Delhi) in the form of confirmation letter from hotel.
b) cash (no CC allowed)
c)photo.
And the card cost 500 rupees, non refundable, amount stored also subject to taxes, so for example, if you paid 1000rupees, you only get 900 something value in the card.
but the card was really value for money, we made 20-30 international calls home without depleting the 1000 rupees .