5 provisions under which Parliament can legislate on a subject.

There are 5 provisions under which Parliament can legislate on a subject included in state list:

Article 249  if the Council of States has declared by resolution supported by not less than two thirds of the members present and voting that it is necessary or expedient in the national interest that Parliament should make laws with respect to any matter enumerated in the State List specified in the resolution, it shall be lawful for Parliament to make laws for the whole or any part of the territory of India with respect to that matter while the resolution remains in force.
Article 250 Parliament shall, while a Proclamation of Emergency is in operation, have power to make laws for the whole or any part of the territory of India with respect to any of the matters enumerated in the State List.
Article 252 If legislatures of two or more states pass a resolution, it shall be lawful for the parliament to legislate on that subject enumerated in state list for the states that passed the resolution.
Article 253  Parliament has power to make any law for the whole or any part of the territory of India for implementing any treaty, agreement or convention with any other country or countries or any decision made at any international conference, association or other body
Article 356 (b) the President may by Proclamation declare that the powers of the Legislature of the State shall be exercisable by or under the authority of Parliament.