Under which Article of the Indian constitution, the Parliament can make laws on State list subject for giving effect to international agreements ?

Article 253 is the answer. It empowers Parliament to make any law for the whole or any part of India to implement treaties, agreements or conventions with other countries, or decisions taken at international conferences, associations or bodies. The word 'any' matters here: this power extends to State List subjects, which is why the question is framed that way.

Why the others are wrong:

• Article 249 lets Parliament legislate on a State List subject in the national interest, but only after the Rajya Sabha passes a resolution by two-thirds of members present and voting. It has no link to treaties.
• Article 250 gives Parliament power over State List subjects during a Proclamation of Emergency under Article 352, and such a law ceases six months after the emergency ends. It is not treaty-linked.
• Article 252 covers legislation for two or more States with their consent. It is about federal consent, not international obligations.

Core concept: Article 51(c) directs the State to respect international law and treaty obligations, and Article 253 gives Parliament the means to honour them even where the subject is a State matter. In Mains, this links to the tension between the Union's treaty power and federal distribution of legislative powers, as seen in environmental and wildlife treaties.

Trap: candidates pick Article 249 because it is the best-known route for Parliament to override the State List in normal times. Remember that 249 needs a Rajya Sabha resolution and is for national interest, while 253 is specifically for treaties.