Section 23(1)(b) in Tamil Nadu Inam Estates (Abolition and Conversion into Ryotwari) Rules, 1965
(b)The deduction on account of the maintenance of irrigation works referred to in sub-section (2) of section 26 shall be made from the portion of the gross annual ryotwari demand relating to the part of the inam estate held by the institution or service-holder. No deduction shall be made, if the irrigation works do not actually serve such part.