( 1 ) THE common question which arises for consideration in this and the connected writ petitions, which are being disposed of by this judgment, is regarding the Constitutional validity of section 3 (1) of the Customs Tariff Act, 1975 (hereinafter referred to as the said Act ).

( 2 ) THE petitioners are importers of various items from abroad. The petitioners of Civil Writ No. 3563 had imported acrylic plastic scrap. Civil Writ No. 3678 is concerned with import of ball bearings, while in C. W. Nos. 3663 and 3645 the items which are imported by the petitioners are blank video casettes. There is no dispute regarding the validity of the import. On the goods arriving in India the petitioners filed the bills of entry. The Customs Authorities required the petitioners to pay the customs duty and, in addition there to, have also asked the petitioners to pay duty levied under section 3 (1) of the said Act. This duty has been calculated not on the C. I. F. value of the goods but on their assessable value as arrived at in accordance with the terms of section 3 (2) of the said Act.

( 3 ) AS already noted above, the principal contention of the petitioners is that the provision