My mother has been told to buy a revolver for self defence?

There might be the possibility of getting a bank security box where people can store valuables, then store a small revolver and ammo. As long as you keep your payments up, you could keep it there for a long time. Some banks have a policy where a bank employee will get the security box for you then wait away from you for privacy. I would look into that. But if they allow such I would be careful to keep it in some container that you can carry it out of the bank without causing alarm. And I would make sure it was never stored there loaded in fact you could omit the ammo and just buy a small box after your done removing it from the bank. I had an uncle who did that overseas.

She can pawn it (if) India has pawn shops. I kept a Browning .22 semi-auto in California pawn shops for over 2 years. Pawn Stars TV show only shows people coming in to sell...not borrow money on collateral item. Pawn shops have a monthly interest rate than can work like a renewal on a loan with fees less than storage facilities.

She doesn`t have to sell her gun. The cartridges?...just buy what you need...no more...then dispose in India.

Find out about India`s laws how long pawn shops have to wait before selling a pawned if late or default on payments.

A hand gun is not a magic talisman that wards off evil. It is a potentially lethal tool that requires a bit of practice and determination to use effectively against another human being. If your mother doesn't have that, she has no use for a gun. If she DOES, then take Bear Crap's advice.

Why not just stay out of India?

(edit: or hire bodyguards)

She only needs to avoid going out alone and to stay out of areas where she does not belong.