I know you got a PM, but in case there are some things not covered.....
Check with your handler and ask if you can get a TLP, a Temporary Landing Permit. This is your "transit visa," but they do not like it, I have had to leave my passport behind and you get a paper........donīt misplace it or start taking hindi lessons.
It has taken up to 5 hours wait to get the TLP, if they arenīt prepared for you in advance.
Not all the airports/States will issue them. Visas are far better, for example, if your aircraft goes tech on you in INdia and you are delayed......you might get kicked out, like in Russia......
Then it becomes REALLY expensive!
Just got my Indian visa, took 5 days for multiple-entry, annual business visa.