The judgment of the Court was delivered by

G. F. COUTO, J. - Petitioners are a company registered under the Companies Act, 1956. By this writ petition under article 226 of the Constitution, they seek the quashing of the assessment orders made by the Sales Tax Officer on August 23, 1985, December 26, 1986 and December 24, 1987, the first relating to the period from January 1, 1981 to December 31, 1981, the second and the third to the period commencing on January 1, 1982 and ending on December 31, 1982 and on December 24, 1987 as regards the period starting on January 1, 1983 and ending on December 31, 1983 in respect of the Central and local sales tax payable by them, as well as a mandamus directing the respondents to withdraw the orders of assessment, and further, to refund to the petitioners the local and Central sales tax paid by them in excess for the period commencing on January 1, 1981, and ending on December 31, 1986 together with interest at the rate of 21 per cent. from the date of collection till the date of refund.

2. Petitioners manufacture under a licence dated July 13, 1967, issued by the Drugs Controller under the Drugs and Cosmetics Act, 1940, which was amen