Which Article of the Constitution of India contains the provision for proclamation of a National Emergency (emergency due to war, external aggression or armed rebellion)?

Introduction / Context:
The Constitution of India provides for three types of emergencies: National Emergency, State Emergency (President's Rule) and Financial Emergency. Each has a specific Article governing its proclamation and operation. This question asks you to identify the Article under which a National Emergency, that is an emergency due to war, external aggression or armed rebellion, can be proclaimed.

Given Data / Assumptions:
- The options mention Articles 350, 352, 360 and 357 of the Constitution.
- The question refers explicitly to National Emergency, not to state emergencies or financial emergencies.
- The student is expected to know the basic scheme of emergency provisions in Part XVIII of the Constitution.
- The correct Article must relate to war, external aggression or armed rebellion affecting the security of India or a part of its territory.

Concept / Approach:
National Emergency is covered under Article 352. It allows the President to proclaim an emergency if satisfied that the security of India or any part of its territory is threatened by war, external aggression or armed rebellion. Article 356 deals with failure of constitutional machinery in States, Article 360 deals with financial emergency, and other Articles are concerned with related matters. The approach is to match the specific type of emergency described in the question with the correct Article number in the emergency provisions.

Step-by-Step Solution:
Step 1: Recall that Article 352 relates to National Emergency on grounds of war, external aggression or armed rebellion. Step 2: Recognise that Article 360 deals specifically with Financial Emergency, which is a different type of emergency. Step 3: Note that Articles 355 to 357 deal with duties of the Union to protect States and with President's Rule, not with the National Emergency described in the question. Step 4: Article 350 is not part of the emergency provisions and deals with language related grievances. Step 5: Therefore, the only Article among the options that provides for proclamation of a National Emergency is Article 352.

Verification / Alternative check:
Any standard textbook on Indian Polity lists Article 352 as the provision for National Emergency and Article 360 for Financial Emergency. Historical references to the National Emergencies proclaimed in India in 1962, 1971 and 1975 all mention Article 352 in connection with the proclamation. The language of the Article clearly refers to war, external aggression and armed rebellion, confirming that this is the correct Article for the type of emergency mentioned in the question.

Why Other Options Are Wrong:
Option A (Article 350) is wrong because it is not part of the emergency provisions; it deals with language related rights and representation to the Governor or President regarding language issues.
Option C (Article 360) is wrong because it deals with Financial Emergency, which is invoked when the financial stability or credit of India or any part of its territory is threatened.
Option D (Article 357) is wrong because it deals with the exercise of legislative powers under a proclamation issued under Article 356 (President's Rule), not with National Emergency under Article 352.

Common Pitfalls:
A common pitfall is mixing up the Article numbers for National and Financial Emergencies, particularly confusing Article 352 with Article 360. Another mistake is to assume that any Article in the 350 range relates to emergencies without recalling that the emergency provisions are clustered mainly between Articles 352 and 360. To avoid such errors, candidates should memorise a simple map: Article 352 for National Emergency, Article 356 for President's Rule and Article 360 for Financial Emergency.

Final Answer:
The provision for proclamation of a National Emergency is contained in Article 352 of the Constitution of India.