The statement "It shall be the duty of every citizen of India to protect and improve the natural environment" refers to which of the following Articles of the Constitution of India?

Introduction / Context:
The Constitution of India not only grants rights but also imposes duties on citizens. Fundamental Duties, listed in Article 51A, include obligations related to national integrity, heritage, and the environment. This question focuses on the duty to protect and improve the natural environment and asks which Article contains this statement.

Given Data / Assumptions:
- The quotation mentions the duty of every citizen to protect and improve the natural environment.
- The question asks for the Article of the Constitution where this duty is mentioned.
- Options list Articles with similar numbering patterns: 50A, 50B, 51A, 51B, and 21A.

Concept / Approach:
Fundamental Duties were inserted into the Constitution by the 42nd Amendment Act, 1976, as Article 51A. Among these duties, Article 51A(g) states that it is the duty of every citizen of India to protect and improve the natural environment including forests, lakes, rivers, wildlife, and to have compassion for living creatures. Therefore, the general reference to the duty to protect the natural environment clearly points to Article 51A.

Step-by-Step Solution:
Step 1: Recall that Fundamental Duties are contained in Article 51A of the Constitution. Step 2: Remember that one of these duties specifically mentions protecting and improving the natural environment and having compassion for living creatures. Step 3: Note that Articles 50A and 50B are not recognised Article numbers in the Constitution in this context, and Article 21A concerns the right to education. Step 4: Therefore, when the statement refers to duty to protect and improve the natural environment, it is pointing to Article 51A.

Verification / Alternative check:
Reading the text of Article 51A(g) in the Constitution confirms the wording about protecting and improving the natural environment including forests, lakes, rivers, and wildlife. Polity textbooks discussing Fundamental Duties quote this clause and highlight its importance in environmental protection, verifying the answer.

Why Other Options Are Wrong:
Article 50A and Article 50B: These are not the standard Article numbers used for Fundamental Duties or environmental duties in the Constitution; they are distractors.
Article 51B: Not the correct reference for Fundamental Duties; Article 51A is the actual Article enumerating them.
Article 21A: Deals with the right to free and compulsory education for children between six and fourteen years of age, not with environmental duties.

Common Pitfalls:
Learners sometimes confuse Article 21, which has been interpreted to include environmental rights, with Article 51A, which lists environmental duties. Another pitfall is mixing up Article numbers because they are similar, especially 51A and 21A. The key is to remember that Fundamental Duties are specifically placed in Article 51A, while rights like education are in 21A.

Final Answer:
The duty of every citizen to protect and improve the natural environment is stated in Article 51A of the Constitution of India.