I know the thread has talked about Delhi, but i'll be arriving into Mumbai and will be staying at the intercontinental at the airport before i head off to a smaller town in Gujarat. I don't mind buying it in the smaller town, but 1. i want to call home when i get to the hotel, and 2. ill be landing on the night before diwali, so im not sure if the stores will be open.

with a us passport and no proof of indian residency (unless a hotel confirmation will count)....how can i get a sim card?

Are there any locations in the airport (for an international arrival) to buy a sim? Do they sell them at the intercontinental hotel? Do i need to show anything?