Section 14(7)(a) in West Bengal Municipal Corporation Act, 2006
(a)one or more Councillors who are the members of such recognised political party have-(i)voluntarily given up his or their membership of such recognised political party, or(ii)joined another recognised political party, or(iii)have exercised the voting right contrary to the manner of voting of the majority of the Councillors set up by such recognised political puny in the Corporation, or