Posting on behalf of a friend who just returned from a trip to India:
"Ganga jamuna (gon-gah joo-mon-ah) is a mix of orange and sweet lime juices. It is the most delicious thing evereverever. Sweet limes are native to India, but I've never seen any here. Ever. Stupid customs wouldn't let me bring any back (I didn't try, but no fruit was clearly explained). I did a search on Google to see if any place imported them.
I read that they are grown a little in the desert in California, but still, I've never seen them. Anybody know where I can buy these in MA? Maybe a shop that specializes on exotic fruits or something?"