law: 45. Right of non-occupancy tenants to make improvements.-
  No non-occupancy tenant shall make any improvement except with the written consent of his landholder:
  Provided that, if such tenant is a sub-tenant, he shall not make any improvement unless-
  (a) it is an improvement which his landholder could himself have made; and
  (b) he has obtained the written consent of his landholder.