Becoming a citizen of India is governed by the Citizenship Act, 1955 and the rules framed under it. The Act provides several legal pathways. Below is a structured, detailed breakdown of each route, eligibility criteria, documentation, and procedural steps.

Citizenship by Birth

Applicable if:

You were born in India under the following conditions:

• Between 26 January 1950 and 1 July 1987
  → Automatically a citizen, regardless of parents’ nationality.
• Between 1 July 1987 and 3 December 2004
  → At least one parent must be an Indian citizen.
• On or after 3 December 2004
  → One parent must be an Indian citizen and the other must not be an illegal migrant.

Procedure:

No application required if eligibility is clear. Citizenship is established through:

• Birth certificate
• Parents’ citizenship documents

Citizenship by Descent

Applicable if born outside India to Indian parent(s).

Conditions:

• If born between 26 Jan 1950 and 10 Dec 1992 → Father must be Indian citizen.
• After 10 Dec 1992 → Either parent can be Indian citizen.
• After 3 Dec 2004 → Birth must be registered at Indian consulate within 1 year.

Procedure:

1. Register birth at nearest Indian Embassy/Consulate.
2. Submit:
   • Parent’s Indian passport
   • Birth certificate
   • Declaration of not holding foreign passport (if applicable)

Citizenship by Registration

This applies to specific categories:

Eligible Categories:

• Person of Indian origin residing in India for 7 years
• Person of Indian origin residing abroad
• Spouse of an Indian citizen (married for 7 years)
• Minor children of Indian citizens
• Overseas Citizen of India (OCI) cardholders meeting residency requirements

Residency Requirement:

Usually, 7 years of residence in India before application.

Procedure:

1. Apply online through the Ministry of Home Affairs (MHA) portal.
2. Submit:
   • Proof of Indian origin
   • Marriage certificate (if spouse category)
   • Valid visa/residence permit
   • Police clearance
3. District-level verification
4. Central Government approval
5. Oath of allegiance
6. Certificate of registration issued

Citizenship by Naturalization (Most Common for Foreign Nationals)

This is the standard route for foreigners with no Indian ancestry.

Eligibility Requirements:

The applicant must:

• Resided in India for 12 years total, including:
  • 11 years in the last 14 years
  • 12 continuous months immediately before applying
• Be of good character
• Have knowledge of a language listed in the Eighth Schedule of the Constitution
• Intend to reside in India
• Renounce previous citizenship (India does not allow dual citizenship)

⚠️ Exception: Government may relax conditions for distinguished service (science, arts, literature, world peace, etc.)

Step-by-Step Procedure (Naturalization)

Step 1: Online Application

• File Form XII on MHA citizenship portal.

Step 2: Document Submission
Includes:

• Passport copy
• Long-term visa
• Residential permits
• Police clearance
• Income proof
• Language declaration
• Affidavit of good character

Step 3: Background Verification

• Local police verification
• Intelligence Bureau clearance

Step 4: Central Government Review

• Ministry of Home Affairs reviews the application
• May request additional documents

Step 5: Oath of Allegiance

• Applicant takes oath under the Second Schedule

Step 6: Citizenship Certificate Issued

• Citizenship legally granted
• Indian passport can then be applied for

Citizenship by Incorporation of Territory

If new territory becomes part of India (historical example: Goa in 1961), residents may be granted citizenship.

Important Legal Notes

Dual Citizenship

India does not permit dual citizenship. However, it offers the Overseas Citizen of India (OCI), which provides long-term visa and economic rights but not full citizenship.

Renunciation

If an Indian citizen acquires foreign citizenship, Indian citizenship automatically ceases.

Revocation

Citizenship can be revoked for:

• Fraud
• Disloyalty to Constitution
• Criminal conviction within 5 years
• Trading with enemy states

Typical Timeline

• Registration: 6–18 months
• Naturalization: 1–3 years (depending on verification)

Governing Authority

All citizenship matters are administered by:

• Ministry of Home Affairs (MHA)
• Indian Embassies/Consulates (for overseas applicants)

To know more about the topic, one may refer to this book.