Section 18(1) in The Water (Prevention And Control Of Pollution) Act, 1974
(1)In the performance of its functions under this Act—(a)the Central Board shall be bound by such directions in writing as the Central Government may give to it; and(b)every State Board shall be bound by such directions in writing as the Central Board or the State Government may give to it:Provided that where a direction given by the State Government is inconsistent with the direction given by the Central Board, the matter shall be referred to the Central Government for its decision.