1) If you have a Public Provident Fund (PPF) account, which you had forgotten about and is dormant, you can revive it by paying the pending subscriptions and penalties.
2) To keep a PPF account active, you need to deposit at least Rs 500 every year. If you fail to do so, a penalty of Rs 50 per year is levied. To reactivate the account, you have to pay the amount due till the date of reactivation.
3) Since the PPF account would have been declared 'inactive' by the bank, reactivating it will require a personal visit and verification by the bank.
4) If your PPF account has already matured, it will not earn any interest from the date of maturity. You cannot reactivate such an account, but will have to pay the penalty to claim the proceeds.
5) If the PPF account is close to maturity, you can apply for an extension, with or without further contribution, for a period of five years from the date of maturity to be able to earn an interest on the accumulated amount.