There are eleven grounds for divorce and they are as follows;

1. Extramarital affair: Section 13(1)(i) of the Hindu Marriage Act deals with extramarital affair or adultery of any sort, engaging in sexual activity other than legally wedded husband / wife to the marriage.  This is one of the most common grounds for divorce in the recent days.  This includes sex outside marriage irrespective of the gender, status, or circumstance applicable to both husband and wife.

2. Cruelty:  Section 13(1)(ia) of the Hindu Marriage Act deals with cruelty.  This involves cruelty by both husband / wife or their family members.  Harassment and the mental agony will have a significant effect on anybody that makes them to take a call on whether to continue with a marriage or not.  This is a common ground in many cases for divorce.  Cruelty involves both physical harassment and mental torture.   Whether the cruelty was done under the influence of alcohol or other reasons can never justify the mental agony and the pain one has to go through.  Any act of cruelty done unintentionally or intentionally cannot be justified.

3. Desertion and willful neglect:  Section 13(1)(ib) of the Hindu Marriage Act deals with desertion.  The husband / wife has deserted the petitioner for more than two years is another ground for divorce.  In many instances, the husband / wife will abandon their relationship either voluntarily or upon the influence or insistence of other family members, which is the most horrible thing to do.  Giving preference for opinion of other family members over their marital relationship is the most foolish thing anybody could think of, instead husband / wife are the ones who should look after their relationship.  Abandoning the loved ones is the most unpleasant thing for the both husband / wife and children.

4. Second Marriage:  Section 17 of the Hindu Marriage Act, deals with second marriage where Husband / wife married while there is a subsisting marriage without taking divorce from the husband / wife from their first marriage making it a punishable offence.  Yes, there are people who are foolish enough to do this.

5. Religious Conversion:  Section 13(1)(ii) of the Hindu Marriage Act, if either, husband / wife ceases to be a Hindu, it is a ground for divorce.

6. Suffers from mental health issues:  Section 13(1)(iii) of the Hindu Marriage Act, If the husband / wife is suffering from any mental disorders, which is making it impossible for husband / wife to cohabit together is one of the strongest reasons for divorce.

7. Suffering from venereal disease communicable in nature:  Section 13(1)(v) of the Hindu Marriage Act deals with diseases which are transmitted.  Some of the well known venereal diseases are Chlamydia, gonorrhea, and HIV.

8. Taken up sainthood:  Section 13(1)(v) of the Hindu Marriage Act deals with renouncement of family.  If any of the husband / wife, has renounced the family and taken up a religious path, then that is a valid ground for divorce.

9. Whereabouts are not known for more than 7 years by those who would have heard normally heard of:  Section 13(1)(vii) of the Hindu Marriage Act deals with those missing people who are not found, not known to be found, missing etc.,  In these circumstances, the husband / wife, can file for a divorce.

10. No cohabitation for more than one year after passing of decree for cohabitation:  Section 13(1A)(i) & (ii) of the Hindu Marriage Act states that if there is a decree for restitution of conjugal right or cohabitation and it was not resumed in the last one year.

11. Married before attaining the age of fifteen and repudiated the marriage after attaining fifteen, but before the age of eighteen years:  Section 13(2)(iv) of the Hindu Marriage Act states that in these cases, divorce can be granted.

Also, if you are interested, go through these sections

Divorce Documents Checklist,

Interim Maintenance for Wife

Interim Maintenance for Child

Application for maintenance

Application for Child Custody