Under the Citizenship Act and related rules, Indian citizenship is formally granted and administered by which authority of the Government of India?

Introduction / Context:
Citizenship determines who is a full member of a State with civil and political rights. In India, citizenship is governed by the Constitution and by the Citizenship Act, along with detailed rules. For competitive examinations, it is important to know which organ or authority of the Government of India actually processes and grants Indian citizenship, especially in cases of registration and naturalisation of foreign nationals who wish to become Indian citizens.

Given Data / Assumptions:
- The question asks about the authority that grants Indian citizenship under the Citizenship Act.
- The options include constitutional offices such as the President and the Prime Minister, and ministries such as the Ministry of Home Affairs and the Ministry of External Affairs.
- The focus is on the administrative agency responsible for citizenship matters, not on broader constitutional provisions relating to citizenship at the commencement of the Constitution.
- It is assumed that the answer should reflect the usual administrative practice followed by the Government of India.

Concept / Approach:
The Citizenship Act of 1955 and its subsequent amendments lay down modes of acquiring citizenship such as birth, descent, registration, naturalisation and incorporation of territory. The implementation of this Act, including processing applications for registration and naturalisation, is entrusted to an administrative ministry. The Ministry of Home Affairs is the nodal ministry for internal security, nationality, and related matters, and it administers the Citizenship Act on behalf of the Government of India. Therefore, the approach is to identify which ministry or office functions as the administrative authority for citizenship, rather than who symbolically represents the country.

Step-by-Step Solution:
Step 1: Note that the President of India is the head of the State but usually acts on the aid and advice of the Council of Ministers and does not personally process citizenship applications. Step 2: The Prime Minister is the head of the Government and leads the Council of Ministers but does not directly handle routine citizenship administration. Step 3: The Ministry of External Affairs primarily deals with foreign relations, consular services abroad and international organisations, and although Indian missions handle some paperwork overseas, the final decisions on citizenship rest elsewhere. Step 4: The Ministry of Home Affairs is explicitly responsible for matters relating to citizenship, naturalisation, and the Citizenship Act, and issues orders, rules and notifications in this regard. Step 5: Therefore, the authority that grants and administers Indian citizenship under the Act is the Ministry of Home Affairs.

Verification / Alternative check:
To verify, one can check standard polity textbooks and official Government websites which clearly state that the Ministry of Home Affairs is responsible for dealing with matters concerning Indian citizenship, including issuing citizenship certificates, handling cases of registration and naturalisation, and implementing the provisions of the Citizenship Act and associated rules. Application forms and procedural guidelines for citizenship are also issued under the authority of the Ministry of Home Affairs. This consistent official practice confirms that the ministry, and not the President or any other ministry, is the correct authority.

Why Other Options Are Wrong:
Option A (The President of India) is wrong because the President does not directly administer citizenship procedures; the President performs functions based on the advice of the Council of Ministers, and decisions on individual applications are taken at the ministerial level.
Option B (The Prime Minister of India) is wrong because, although the Prime Minister heads the Government, the day to day administration of citizenship matters is delegated to the Ministry of Home Affairs and its officials.
Option D (The Ministry of External Affairs) is wrong because it deals mainly with India's external relations, consular services and policies relating to foreign countries, not the internal legal process of granting citizenship, which falls under the Ministry of Home Affairs.

Common Pitfalls:
A frequent mistake is to assume that ceremonial or top level political offices such as the President or the Prime Minister personally take all important decisions, including those on citizenship. Another pitfall is to confuse the role of Indian embassies, which may forward applications and verify documents, with the authority that actually grants citizenship. Some candidates also wrongly associate citizenship with the Ministry of External Affairs simply because foreign nationals are involved, without recognising that citizenship is primarily an internal security and nationality question handled by the Ministry of Home Affairs. Remembering the administrative division of responsibilities among ministries helps avoid these errors.

Final Answer:
Indian citizenship is formally granted and administered by the Ministry of Home Affairs under the Citizenship Act and related rules.