The judgment of the Court was delivered by

U. L. BHAT, C.J. - Petitioner is a partnership firm engaged in manufacturing and processing of coal into coke. Petitioner is a dealer registered under the Assam Finance (Sales Tax) Act, 1956 (for short "the Act') and under section 7 of the Central Sales Tax Act, 1956 (for short "the Central Act"). Sales by the Petitioner would be liable for sales tax under the Act. The Act was amended by the Assam Industries (Sales Tax Concessions) Act, 1986, that is Assam Act 1 of 1987, for short "the 1987 Act". By one of the amendments section 3B was introduced in the Act. This provision enables the State Government by notification to grant exemption to dealers in respect of sales of goods produced by the dealer in any new industrial unit for a period of five years from the date of commencement of the production in the unit. The State Government published Notification No. FTX. 28177/Pt.II/40 in the Assam Gazette, Extraordinary dated August 1, 1988, directing that no dealer shall be liable to pay tax under the Act in respect of sales of goods produced by him in any new industrial unit in Assam for a period of five years from the date of commencem