Section 23(1)(c) in The Chennai Metropolitan Water Supply and Sewerage Board's Water Tax and Sewerage Tax (Levy and Collection) Regulations, 1991
(c)If such date falls within first four month of the half year, the owner shall subject to notice being given in sub-clause (a) be entitled to remission of so much not exceeding half of the tax or enhanced tax as the case may be payable in respect of the building only, for that half year as is proportionate to the number of days in that half year preceding such date.