1. A decree of foreign court dissolving a marriage is valid in India for all legal and practical reasons. Since it was a mutual consent divorce you require no declaration from the Indian courts, but if you want one then you may file a suit for declaration in India to seek a declaration that the decree of US court is in compliance with the Indian law.
2. The suit has to be filed before the court within whose jurisdiction the marriage took place or where the spouses last resided together.
3. If you only want to delete the ex-spouse's name from the passport then you can apply to the RPO with a certified copy of US decree.