Pius, J.

The petitioner, a company engaged in the business of manufacture and sale of mattresses and other foam products, has filed this writ petition under Article 226 of the Constitution of India seeking, inter alia, the following reliefs:-

(i) A declaration that Section 12(A) of the Sikkim Industrial Promotion and Incentive Act, 2000 (Act No. 18 of 2000) as amended by the Sikkim Industrial Promotion and Incentive (Amendment) Act, 2007 (produced as Annexure P-15 in the writ petition) by section 4 thereof as ultra vires the Articles 14 and 19 (1) (g) of the Constitution of India and violative of the doctrine of promissory estoppel and quash the same.

(ii) A writ of certiorari striking down the Assessment Order dated 08.02.211 for the period of April 2003 to March 2005 issued by third respondent.

(iii) A writ of certiorari striking down order dated 25.04.2011 issued by third respondent on the Review Petition filed by the petitioner holding that the amount of sale declared in Form-C is a primary information received from party of transaction while the amount of sale declared in the return is only report of the actual sale, therefore, in case of any variation, the former should p