Explanation:

301. Freedom of trade, commerce and intercourse. Subject to the other provisions of this art, trade, commerce and intercourse throughout the territory of India shall be free.
302. Power of Parliament to impose restrictions on trade, commerce and intercourse. Parliament may by law impose such restrictions on the freedom of trade, commerce or intercourse between one State and another or within any part of the territory of India as may be required in the public interest
303. Restrictions on the legislative powers of the Union and of the States with regard to trade and commerce (1) Notwithstanding anything in Article 302, neither Parliament nor the Legislature of a State shall have power to make any law giving, or authorising the giving of, any preference to one State over another, or making, or authorising the making of, any discrimination between one State and another, by virtue of any entry relating to trade and commerce in any of the Lists in the Seventh Schedule 304. Restrictions on trade, commerce and intercourse among States Notwithstanding anything in Article 301 or Article 303, the
Legislature of a State may by law (a) impose on goods imported from other States or the Union territories any tax to which similar goods manufactured or produced in that State are subject, so, however, as not to discriminate between goods so imported and goods so manufactured or produced; and But then Article 304 (b) allows state legislatures to restrict trade and commerce on grounds of public interest.
(b) impose such reasonable restrictions on the freedom of trade, commerce or intercourse with or within that State as may be required in the public interest: Provided that no Bill or amendment for
the purposes of clause shall be introduced or moved in the Legislature of a State without the previous sanction of the President