Section 89(b) in The Howrah Municipal Corporation Act, 1980
(b)the annual value of any building not erected for letting purposes and not ordinarily let, shall be deemed to be five per cent, on the sum obtained by adding the estimated present cost of erecting the building, less a reasonable amount to be deducted on account of depreciation (if any), to the estimated present value of the land valued with the building as part of the same premises :
