The husband did a ‘Marriage deed’ (whatever that means) separation with his first wife and married the second woman.

13.1 At the outset it is required to be noted that the appellant filed the marriage petition for a declaration to declare her marriage with the respondent as null and void on the ground that, at the time of their marriage, the first marriage of the respondent with his first wife was subsisting; that the  respondent committed a fraud and suppressed the material fact of his first marriage, and in fact, in the registration form he stated himself to be a bachelor.

Citations: [(2019) SCC Online SC 329]

Other Source links: https://indiankanoon.org/doc/163532688/ or https://www.casemine.com/judgement/in/5c8148999eff4345648def96