Nice one
This DLC unlocks playing as an Indian ruler, using three new religions (jain, buddhism, and hindu), an indian theme UI when playing as a character with indian culture, and a bunch of new events when playing as an indian and a few when not.
Do note that you can still invade India with the expanded steppe area and have to deal with the new religions without buying the DLC.
Pick this up when on a great sale or if you really want to play an Indian and sacrifice people to Kali.