In reply to Godwin:
Also make sure that if you go with a UK SIM, that your payment plan covers roaming abroad. I've lost count of the times I've lent my phone to other group members while they sorted that out with their UK provider.
Last time I was in India (I think 2018) it had just become impossible to get the SIM at the airport, however we found a Mr Fixit who got us the necessary SIMs and met us at the airport with them. Possibly your hotel or wherever could help - definitely worth a call before you travel.
An Indian SIM is highly preferable imo, and coverage appears to be everywhere that I've been, even in the mountain. You can picture the scene - shepherds, fire, unnameable boiling brown liquid, goats, doggies, stars, chapatti, young Indian helpers all on the phone to their girlfriends.
ff