I doubt if the telecom regulations in India allow for this. The phone numbers have to be mapped to a verified subscriber ID, and mobile telephone companies are very particular when it comes to KYC regs. There was also a recent report that all new and existing subscribers will have to (re) validate their identity using AADHAR within the next year or so.

You'll probably fall afoul of multiple laws. Strongly encourage you to check with a telecom LE before you commit to the tech stack.

In the US, burner apps are very easy to use. I remember using an Android application called burner to give a burner number to website sign ups. So someone has already solved this. Again, I don't think this service will be legal in India.

http://www.dot.gov.in/access-services/subscriber-verificatio...