One can activate an inactive bank account by doing basic banking activities such as cash withdrawal or deposit, funds transfer or bill payment. Some banks give you the option to request for activation of your account through Internet banking. You can even call the customer care or contact the bank branch. In case of a dormant account, you may have to submit a written request along with identity proof. Your signature may also be verified to activate the account.
Even after your account turns inactive or dormant, interest, if any, will be credited to your savings account regularly. And last year, the RBI had asked banks not to levy penal charges for non-maintenance of minimum balances in any inoperative account.
From a tax point of you, remember that this year, while filing your income tax return, you have to give details of all your savings and current accounts including dormant and inactive ones. According to income tax laws, details of all bank accounts, excluding those that have been non-operational for over three years, held in India at any time during the previous year should be provided in the return.