You can deposit between ₹500 and ₹1.5 lakh each financial year. Deposits qualify for 80C under the old regime, and interest and maturity proceeds are tax-free. The rate is reviewed every quarter. After 15 years the account can be extended in blocks of 5 years.
Finance glossary
What is Public Provident Fund (PPF)?
A government-backed 15-year savings scheme with tax-free interest, currently paying 7.1% a year.