Provided that no Bill or amendment for the purposes of clause (b) shall be introduced or moved in the Legislature of a State without the previous sanction of the President.
305. Nothing in articles 301 and 303 shall affect the provisions of any existing law except in so far as the President may by order otherwise provide.
306. Notwithstanding anything in the foregoing provisions of this Part or in any other provisions of this Constitution, any State specified in Part B of the First Schedule which before the commencement of this Constitution was levying any tax or duty on the import of goods into the State from other States or on the export of goods from the State to other States may, if an agreement in that behalf has been entered into between the Government of India and the Government of that State, continue to levy and collect such tax or duty subject to the terms of such agreement and for such period not exceeding ten years from the commencement of this Constitution as may be specified in the agreement:
Provided that the President may at any time after the expiration of five years from such commencement terminate or modify any such agreement if, after consideration of the report of the Finance Commission constituted under article 280, he thinks it necessary to do so.
307. Parliament may by law appoint such authority as it considers appropriate for carrying out the purposes of articles 301, 302, 303 and 304, and confer on the authority so appointed such powers and such duties as it thinks necessary.
Effect of articles 301 and 303 on existing laws.
Power of certain States in Part B of the First Schedule to impose restrictions on trade and commerce.
Appointment of authority for carrying out the purposes of articles 301 to 304.