In Delhi, as per Indian law, there are several legal grounds for divorce under different personal laws, such as the Hindu Marriage Act, the Special Marriage Act and the Indian Divorce Act. Here are the primary grounds for divorce:

Adultery:

One spouse engaging in a consensual relationship with someone outside the marriage is a valid ground for divorce. 

Cruelty:

This includes physical or mental harm inflicted by one spouse on the other. It can encompass a range of behaviours, from verbal abuse to severe emotional distress. Having an experienced advocate in Delhi for divorce cases can help present your case effectively.

Desertion:

If one spouse has abandoned the other without reasonable cause for a continuous period (typically two years), this can be grounds for divorce. 

Conversion:

If one spouse converts to another religion, the other spouse has the right to file for divorce under the Hindu Marriage Act .

Mental Disorder:

If a spouse is suffering from a severe mental disorder, which makes it impossible to live together, the other spouse can file for divorce.

Incurable Diseases:

If one spouse suffers from an incurable disease like leprosy or a sexually transmitted disease, the other spouse may seek divorce.

Separation:

Continuous separation for a specified period can also serve as grounds for divorce. For instance, in mutual consent divorces, both parties agree to end the marriage amicably after a period of living apart.

When considering divorce, consult an experienced advocate in Delhi for divorce cases to understand the legal grounds applicable to your situation and to navigate the complexities of the legal process.