Mutual Divorce is not possible under Christian Marriage Act. Rather the couple should file application under Sec 10 A of Indian Divorce Act. Still, the couple has to go through 2 years of separation before seeking the divorce in Mutual grounds.
Supreme Court has urged Centre to amend the law to make the period of separation equivalent to that of other laws i.e. 1 year of separation.
For contested divorce, grounds can be Adultery, Cruelty, Desertion, Impotency and Chronic Disease.