I recently tried out the Altitude lounges, which are accessible using the ICICI Bank Jet Airways Sapphiro Amex.
Here are some pictures and a short review:
a)
Mumbai Terminal 1A
b)
Delhi Terminal 3
I liked them a lot, I wish they had unlimited access rather than only 4 trips on the sapphiro and 2 on the rubyx. Would go back in a jiffy.