In this batch of cases the constitutional validity of clause (b) of sub-section (2) of section 8 of the Central Sales Tax Act, 1956 and of the opening words of sub-section (4) of that section which make sub-section (1) inapplicable in certain contingencies is raised. In Larsen and Toubro Ltd. v. Joint Commercial Tax Officer 1, to which one of us was a party, this Court struck down sub-sections (2) (2-A) and (5) of section 8 on the ground that they violated Articles 301 and 303 (1) of the Constitution. This was on the view that the differential rates or exemptions in various States laid an unequal burden on same or similar goods which affected their free movement or flow of inter-State trade and commerce. It was pointed out that the differential rates or exemptions obtaining in the several States if automatically applied by virtue of section 8 (2) to Central taxation, they would certainly have the effect of discriminating between the goods of one State and the goods of another and might affect the free flow of trade in such goods as between the States and that further sub-sectoins (2-A) and (5) of section 8 only aggravated the discrimination. Neverthe less that case is