law: 28. Power to exempt.-
  Where the Central Government is of the opinion that it is necessary or expedient so to do either in the public interest or having regard to the peculiar circumstances of the case, it may, by notification, and subject to conditions, if any, as may be specified in the notification, exempt 1[any credit institution or any class of credit institutions or any interest on any category of loans or advances] from the levy of interest-tax:
  Provided that no such exemption shall be made except on the recommendation of the Reserve Bank of India.