How much you can get
Cancellations announced less than two weeks ahead pay INR 5,000, 7,500 or 10,000 for a scheduled flight time up to 1 hour, 1–2 hours or longer, or the base fare plus fuel charge if that is lower; nothing if the alternative flight leaves within 2 hours of the original time. Denied boarding pays 200% of the one-way base fare plus fuel charge (up to INR 10,000) if the alternative leaves within 24 hours, 400% (up to INR 20,000) after that, and nothing if it leaves within 1 hour. Delays give meals, hotels or a refund, not cash.
Source: www.dgca.gov.in. This is a summary, not legal advice.
How to claim it yourself
Contact the airline; if it doesn’t resolve the issue, file a grievance on the AirSewa portal.
The claim services we work with (AirHelp, Compensair) take EU and UK cases. Under these rules you claim from the airline directly, which is free.