Section 175(1) in The Calcutta Municipal Corporation Act, 1980
(1)Notwithstanding anything to the contrary contained in this Chapter, the annual value of any land comprised in a thika tenancy with hut or building made thereon, either in a bustee or otherwise, shall be deemed to be the gross annual rent at which such land with hut or building made thereon may reasonably be expected to let from year to year less ten per cent, of such annual rent to maintain the said hut or building in a state to command such gross rent.