Regarding Divorce on mutual consent

Its a registered marriage, you can copy of marriage certificate from Municipal office/marriage regration office.

For mutual divorce you have to take help of a local lawyer to file mutual divorce petition in local court. It cannot be instant but takes minimum 6-8 months provided your married atleast a year ago. Good luck.

What is the Mutual Divorce Procedure in India?

1. Step 1: Filing a Divorce Petition. ...
2. Step 2: Court hearing and inspection. ...
3. Step 3: Statement Records. ...
4. Step 4: First Motion. ...
5. Step 5: Second Motion and Final Hearing. ...
6. Step 6: Divorce Decree.

Obtain duplicate copy of marriage registration certificate from the office of Registrar of Marriages, where it was registered and file a petition for divorce on mutual consent through a local prudent lawyer.

Hi,

You will not get a duplicate marriage certificate but can apply forcertifed copies of the same at the registrar officce of the place where you got married.  It's validity is same as that of the original marriage certificate.  

Once you receive the certified copy of the marriage, you may apply for divorce by mutual consent.

Best regards,
Megha  

First of all Get a local lawyer engaged

He will arrange for the Duplicate marriage certificate and in my opinion you should explore the possibility of Judicial Separation first.

If nothing is positive then Decree for Judicial Separation will itself work as Ground for Divorce 

Thanks

Advocate Pallabh Haldar