law: The Delhi Municipal Corporation Act, 1957
  167. What buildings, etc., are to be deemed vacant.-
  (1) For the purposes of sections 164 and 165, no land, building or tenement shall be deemed vacant if maintained as a pleasure resort or town or country house or be deemed unproductive of rent if, let to a tenant who has a continuing right of occupation thereof, whether he is in actual occupation or not.
  (2) The burden of proving the facts entitling any person to claim relief under section 163, or section 164, or section 165, shall be upon him.