Section 5(4) in The Water (Prevention And Control Of Pollution) Act, 1974
(4)A member of a Board, other than the member-secretary, may at any time resign his office by writing under his hand addressed—(a)in the case of the chairman, to the Central Government or, as the case may be, the State Government; and(b)in any other case, to the chairman of the Board,and the seat of the chairman or such other member shall thereupon become vacant.
