In India money in the bank gains interest which is unavoidable. Can I give that interest money to Madarasa, poor people marriages, poor relatives,etc

Interest monies must be given to the poor and needy who are eligible to accept Zakaat without the intention of reward. However, interest received from government institutes, eg. post office could be used to offset government taxes. Interest received from private banks cannot be used to offset taxes. It may be used to offset interest charged from the same bank.

and Allah Ta'ala Knows Best
Mufti Ebrahim Desai