I found below info on the net
http://www.worldairportguide.com/air...AV_Airport=247

Executive lounges with business facilities are located in Terminal 1 halls A and B. The Maharaja Lounge is situated in transit area of Terminal 2; other lounges are available. Conference and banqueting facilities are available at the Centaur Hotel (tel: (0)11 565 2223), is situated near Terminal 2.


Also, I was in DEL about 2 years ago & visited one of the lounges.
crowded but otherwise nice.don't remember if had showers or not.