Section 139(2)(a) in The U.P. Municipalities Act, 1916
(a)in the case of partial exemption, by means of the deduction from the total amount of the consolidated tax which would otherwise be leviable or assessable in respect of any buildings or lands or both to which the exemption applies, of a proportionate part, corresponding to the exemption, of the amount which might otherwise have been assessed on account of the single tax; and