There are some discussion about India on FlyerTalk -- I was thinking about an out and back to BOM with the $2100 business class RT fare that just ended. But the messages suggested that while XXX-DEL or BOM-YYY would work and you could stay in the transit area, that XXX-DEL or BOM-XXX might cause a problem at checkin because the airline wouldn't see it as transit.
I decided to spend a day in BOM and see a bit of the place instead of booking the out and back. Google twov BOM and you get pointed to several tripadvisor discussions that don't have a definitive answer. I was more concerned with not being allowed on the airplane in AMS than dealing with immigration at BOM.
As airmotive notes -- online visas are easily available for India.