Explanation:

The State List or List-II is a list of 61 items (Initially there were 66 items in the list)  in Seventh Schedule to the Constitution of India. The legislative section is divided into three  lists: Union List, State List and Concurrent List. Unlike the federal governments of the United States,  Switzerland or Australia, residual powers remain with the Union Government, as with the Canadian  federal government. If any provision of a law made by the Legislature of a State is repugnant to any  provision of a law made by Parliament which Parliament is competent to enact, or to any provision  of an existing law with respect to one of the matters enumerated in the Concurrent List, then, the  law made by Parliament, whether passed before or after the law made by the Legislature of such  State, or, as the case may be, the existing law, shall prevail and the law made by the Legislature of  the State shall, to the extent of the repugnancy, be void. There is an exception to this in cases  “where a law made by the Legislature of a State with respect to one of the matters enumerated in  the Concurrent List contains any provision repugnant to the provisions of an earlier law made by  Parliament or an existing law with respect to that matter, then, the law so made by the Legislature  of such State shall, if it has been reserved for the consideration of the President and has received  his assent, prevail in that State. Provided that nothing in this clause shall prevent Parliament from  enacting at any time any law with respect to the same matter including a law adding to, amending,  varying or repealing the law so made by the Legislature of the State.”