Parliament and a State Legislature both enact laws on a subject in the CONCURRENT List, and the State law is repugnant to the earlier Central law. Under Article 254 of the Constitution, the law that prevails is:

Article 254 of the Constitution deals with the repugnancy between a Union law and a State law on a matter in the CONCURRENT LIST. As a general rule, the earlier Union law prevails over the State law to the extent of repugnancy (Article 254(1)), since Parliament's law stands. However, Article 254(2) provides an exception: if the State law, having been reserved for and having received the ASSENT of the PRESIDENT, prevails in that State. The presidential-assent carve-out is the operative exception, and its continued operation is subject to Article 254(2) second part when a later Union law is enacted. Repugnancy resolution is a core federalism topic.