NRI Marriage

You can perform the marriage according to your religious rites and get the same registered with Registrar of Marriages.

Certificates showing age proof,  Invitation if any printed, Photographs of  performance of marriage like exchange of garlands, Sutra Dharan, Walking around Holy fire and marriage with elders , if the function is conducted in a function hall their receipts, witness of atleast two independent elders that are having identity proofs (AADHAR)  are essential.  The witnesses, the couple must visit Registrar's office with above documents.

Once the marriage registrar gives a certificate it is a bonafide proof for marriage.  You can contact the marriage registrar, and take both bride and bride groom direct to the Registrar's ofice for signing in their register.  If you can contact Registrar of Marriages with invitation and establish a relationship, the Certificate will be delivered on same day.

Marrying a Polish woman, not a good idea, this my personal opinion.

Secondly to marry in Poland the Indian man can get married under the Foreign Marriage Act,1969 with the foreign national according to civil form of marriage. No change of religion for either party required. the Marriage is according to Indian law and it will be duly registered and valid Marriage Certificate under the Act will be issed to the parties. For this reason no further registration required in India.

As to where to get the marriage solemnised and registered in Poland, just the Indian High Commission where both parties to marriage meet the Marriage officer, one of the Official appointed for the job who will take the Notice for marriage, after one month in presence of only 3 witnesses will marry them in a very simple cermoney and register the marriage. Proof of age of both parties, addresses of both, unmarried status of both will be required. Identity proof of 3 witnesses will be required.

You talk of Sanatan Dharam Marriage in India, how that is possible when she is a Christian, not a Hindu, you if ask her to change her religion she will not agree and marrying a Christian with Hindu according to Sanatan Dharam will be mockery of Hindu religion, playing with religious sentiments of invited Hindu guest.

You can benefit from above.

Subsequently;

Visit Local O/o Marriage Registrar and inquire in person…

And discuss with a very able  senior LOCAL counsel of unshakable repute and integrity specializing in Family  matters  and well versed with latest citations, LOCAL applicable rules/laws/ … and having successful track record…. and worth his/her salt…..and show the case related docs etc etc for a considered opinion..in person