You have to wait One year completition period for filing a legal valid divorce petition. Otherwise you can opt declaring the marriage is null and void.
Annulment or Nullity of marriage means that the marriage has not happened at all. After getting the annulment or nullity decree, the status of the individual is UNMARRIED/ SINGLE,
Conditions of the annulment of the marriage are:
a. The marriage has not been consummated ( no sexual relationship has occurred between the husband and wife)
b. It should not have been in the prohibitive relationships (Husband and wife cannot be as brother and sister, like first or second cousin, or through same father and different mother etc., unless accepted by the caste)
c. This marriage should not have happened through fraud or force and without the consent of both the individuals to the marriage.
d. The marriage should not have happened through the concealment of the facts. (like either parties were married before and later divorced, or have a child through previous relationship)
e. The parties of the marriage should not have the contagious disease which cannot be cured within the specified period of 1 year.
f. The parties of marriage should not be impotent or have the disease which can be unable to bear the family.
g. The parties of the marriage should not be of unsound mind.
h. The parties of the marriage should not be in any marriage earlier, and if the marriage has happened, the divorce should have been happened (except for Muslims) before the second marriage.
Divorce by Mutual Consent is the easiest way to get a divorce, in this both parties work out their terms on which they agree to part ways- file petition in the court, which is finalised in 6 months. However there may be cases where the decision to part may not be a mutual one, and it is only one party who considers the union to be troublesome and worth getting rid off. Such situations lead to Divorce being contested.