Section 34(2)(ii) in The Calcutta Metropolitan Water And Sanitation Authority Act, 1966
(ii)in the case of such building, the gross annual rent shall be deemed to be five per cent, of the value of the building obtained by adding the estimated cost of erecting the building at the time of assessment less a reasonable amount to be deducted on account of depreciation, if any, to the estimated present market value of the land with the building as part of the same premises.