The judgment of the court was delivered by

SETH, J. - This petition under article 226 of the Constitution is directed against the orders dated 26th June, 1973, and 13th December, 1973, passed by the Sales Tax Officer assessing the petitioner to tax under the Central Sales Tax Act and thereafter refusing to rectify the same.

The petitioner-company manufactures toughened glasses and mirrors in its factories at Allahabad and Calcutta. It has a branch office at Delhi. In the normal course of business, it effected certain inter-State sales of toughened glasses manufactured by it at Allahabad. The Sales Tax Officer, by his order dated 26th June, 1973, determined the turnover of such inter-State sales for the year 1970-71 and assessed the petitioner to sales tax accordingly. Subsequently, the petitioner, relying upon a notification dated 9th January, 1970, issued by the State Government in exercise of its powers under section 4-A of the U.P. Sales Tax Act, declaring that the turnover in respect of mirrors and toughened glasses manufactured by the petitioner at Allahabad shall be exempt from payment of sales tax for a period of three years with effect from February, 1969, claimed