law: 90. Permission of the Chairperson to become void in certain cases.
  The permission granted under section 89 shall become void in the following cases, namely:
  (a) if the advertisement contravenes any bye-law made under this Act;
  (b) if any material change is made in the advertisement or any part thereof without the previous permission of the Chairperson;
  (c) if the advertisement or any part thereof falls oth erwise than through accident;
  (d) if any addition or alteration is made to, or in the building, wall, hoarding, frame, post or structure upon or over which the advertisement is erected, exhibited, fixed or retained if such addition or alteration involves the disturbance of the advertisement or any part thereof; and
  (e) if the building, wall, hoarding, frame, post or structure over which the advertisement is erected, exhibited, fixed or retained is demolished or destroyed.