To obtain an Overseas Citizen of India (OCI) card as a citizen of the US, UK, Canada, or Europe with Indian ancestry, you must meet specific eligibility criteria under NRI Immigration regulations.

• Citizenship History: You are eligible if you were an Indian citizen at any time after January 26, 1950, or were eligible to become an Indian citizen on January 26, 1950. You are also eligible if you belonged to a territory that became part of India after August 15, 1947. Additionally, this applies to your children, grandchildren or great-grandchildren​.
• Minor Children: Minor children are eligible if at least one parent is an Indian citizen. This includes minor children of such individuals mentioned above.
• Spousal Eligibility: If you are a spouse of an Indian citizen or an OCI cardholder and your marriage has subsisted for at least two years prior to applying, you are eligible​.

However, individuals with a background or ancestry linked to Pakistan or Bangladesh are excluded. Active or retired foreign military personnel and certain government contractors in defense sectors are also not eligible under NRI Immigration regulations​.

The application process requires filling out an online form, submitting supporting documents that prove your Indian ancestry, and meeting photo specifications. The application and all required documents must be submitted to the appropriate Indian mission or consulate. Ensure that all documents are complete and meet the required criteria to avoid processing delays.