Question related to Hindu Marriage Act - Bipolar disorder

I had arranged marriage, hindu by religion. My wife is having bipolar disorder. This fact was concealed by my wife & her family before finalizing the marriage we had specifically asked whether her medical report are normal . Even today after 2 years of marriage she has concealed the fact. The symptoms are she is experiencing mood swings, anger, anxiety, migraines, guilt, loss of interest or pleasure in activity, behavioral issue, spells of crying , depression, manic episode, unwanted thoughts, racing thoughts, regular episodes of extreme overeating and feeling of loss of control about eating. This facts were deliberately concealed and not told in spite of family meetings. Specific questions asked to girls parents about the medical reports ; whether they are normal or not. pl. advice whether any provision is available to treat the marriage as null & void and what is the time limit. What is the legal remedy in defence to applicant ( i.e husband) in this case of cheating and fraud.