Upvote:0
Yes you can stay at airside if you have a connecting flight, but do ask the airline service provider about the same. As in my case I got my baggage shifted without me even bothering about the luggage. So in that case you can continue your journey without entering India (Though you're missing out on the chance of looking at the world's biggest democratic country). Bon Voyage
Upvote:2
If you have to re-check your baggage because your tickets were booked separately, you will have to enter India. This is something to check with Indigo, your airline.
Also 3.5 hours should be enough to make your connection.