law: Transfer of Property Act, 1882
  66. Waste by mortgagor in possession
  A mortgagor in possession of the mortgaged property is not
  
  liable to the mortgagee for allowing the property to deteriorate; but he must
  
  not commit any act which is destructive or permanently injurious thereto, if
  
  the security is insufficient or will be rendered insufficient by such act.
  Explanation: A security is insufficient within the meaning
  
  of this section unless the value of the mortgaged property exceeds by
  
  one-third, or, if consisting of buildings, exceeds by one-half, the amount for
  
  the time being due on the mortgage.