I.A. Ansari, J.

Case of the writ Petitioners:

1. In the nutshell, the case of the writ petitioners may be stated as follows : -

The writ petitioner No. 1 is a limited Company, incorporated under the Companies Act, 1956, having its registered office at Guwahati, Assam, with the petitioner No. 2 as its Director. In the year 1991, the State Government announced a new Industrial Policy called "Industrial Policy and Incentive Scheme of 1991" and gave certain incentives, in the form of sales tax exemption, to new industrial Unit to be established within the State of Assam after 01.04.1991. This incentive of sales tax exemption was granted, for a period of 7 years, on the sale of finished products as well as on purchase of the raw materials. After enactment of the Assam General Sales Tax Act, 1993 (hereinafter referred to as "the AGST Act, 1993"), the Government of Assam, in exercise of the powers vested in it under Section 9(4) thereof, framed a Scheme named "Assam Industries (Sales Tax Concessions) Scheme, 1995" (hereinafter referred to as "the Scheme of 1995") granting relief of exemption of sales tax, both Central as well as State, for a period of 7 years, to the new industrial Units, established on or after 01.04.1991, on fulfillment of the criteria of eligibility prescribed therein. In response to the Scheme of 1995, so announced, the petitioner Company undertook steps to establish a new industrial Unit at Bettola, Guwahati, and prepared a project report (Annexure-II to the writ petition) for manufacture of washed clean coal by processing and washing of raw coal, lump coal and medium coal so as to bring down the ash contents thereof from as much as 25% to 5%, there being heavy demand for washed coal in the local market as well as in the other States of the country and also in Bangladesh. The petitioner Company purchased a plot of land at Beltola and established a new industrial Unit, which was granted a permanent registration certificate, dated 18.06.1996, by the Director of Industries, Government of Assam, as a tiny Unit. The petitioner Company also obtained licence as well as necessary "No Objection Certificate" from Gauhati Municipal Corporation to establish the said Unit. After fulfilling all necessary formalities including the clearance/approval from the authorities, such as, the Pollution Control Board, Chief Inspector of Factories, the petitioner Company started commencement of its production with effect from 05.02.1996. On an application being made by the petitioner Company for necessary Eligibility Certificate from the Department of Industries in order to enable the petitioner Company to obtain sales tax exemption and, upon being satisfied that all the conditions for issuance of Eligibility Certificate had been fulfilled, necessary Eligibility Certificate (Annexure-VII to the writ petition) was granted by the competent authority, on 31.03.1998, entitling thereby the petitioner Company to receive sales tax exemption from 05.02.1996 to 04.02.2003, (i.e., for a period of seven years from the date of commencement of the Unit), the Eligibility Certificate, so granted, clearly mentioning therein that the finished product is "washed clean coal" and the raw materials are "raw coal, lump coal and medium coal". Thereafter, the petitioner Company also received authorisation certificate (Annexure-VIII to the writ petition) issued by the competent authority of the Sales Tax Department, on 03.09.1999, granting sales tax exemption to the petitioner Company aforementioned for the period aforementioned. Prior to the issuance of the said authorisation certificate by the Superintendent of Taxes, Jalukbari, Guwahati, the petitioner Company paid security in respect of every vehicle carrying the finished goods manufactured by the petitioner Company in its said industrial Unit and crossing barrier of the check gates, the petitioner Company having, thus, paid about Rs. 2 crores during the assessment years 1996-97 and 1998-99. As the peti