P. K. MISRA, J. - In order to appreciate the contentions raised on behalf of the parties, it is necessary to notice the relevant provisions in a historical perspective. Section 2(1)(a) of the Tamil Nadu Additional Sales Tax Act, 1970 as it stood prior to August 1, 1996, was to the following effect :

"Section 2. Levy of additional tax in the case of certain dealers. - (1)(a) The tax payable under the Tamil Nadu General Sales Tax Act, 1959 (Tamil Nadu Act 1 of 1959) (hereinafter in this section referred to as the said Act), shall, in the case of a dealer whose taxable turnover for a year exceeds ten lakhs of rupees, be increased by an additional tax calculated at the following rates, namely :

Rate of tax

(i) Where the taxable turnover exceeds ten 1.5 per cent of the lakhs of rupees, but does not exceed one taxable turnover crore of rupees :

Provided that no additional tax shall be payable under this item for the first ten lakhs of rupees of the taxable turnover.

(ii) Where the taxable turnover exceeds one 2 per cent of the crore of rupees but does not exceed five taxable turnover crores of rupees.

(iii) Where the taxable tu