For an offence under Section 494 both the marriages must be legal and valid. Unless these ingredients of Section 494 are satisfied, the accused cannot be punished for an offence of bigamy under the same. If the said section requires a strict proof of the validity of the second marriage, it is not understandable why such a strict proof is not required for the first marriage also. It would, therefore, follow that if for the proof of the second marriage, it is necessary for the complainant to prove all the essential requirements of a legal and valid marriage, then by the same standard and by the same reasoning it is necessary for him to prove as a fact all the essential requirements to show that the first marriage was also performed validly.
Bombay High Court
Godawari vs State Of Maharashtra And Others on 24 September, 1984
Bench: H Dhabe
See JUDGMENT Here : https://www.lawweb.in/2012/04/bigamy-proof-of-solemnization-of-both.html