Exemption for provident fund interest applies prospectively; enhanced prescribed rates exempt only amounts credited after notification takes effect. Interest credited to an employee's account in a recognised provident fund is exempt from income tax subject to the ceiling of one third of salary or the rate prescribed by the Central Government under the Fourth Schedule. Notifications increasing the prescribed rate operate prospectively; exemption at an enhanced prescribed rate applies only to interest amounts credited to individual accounts on or after the notification's effective date.