(1) Subject to the other provisions of this Act, with effect from the appointed day,-

(a) every dealer-

(i) who has been liable immediately before the appointed day to pay tax under section 4 or section 8 of the Bengal Finance (Sales Tax) Act, 1941, (Ben. Act VI of 1941) and who would have continued to be so liable on such appointed day under that Act had this Act not come into force, or

(ii) whose gross turnover during a year first exceeds the taxable quantum as applicable to him under the Bengal Finance (Sales Tax) Act, 1941, on the day immediately preceding the appointed day,

(b) every dealer registered under the West Bengal Sales Tax Act, 1954, (West Ben. Act IV of 1954) who is in possession of a registration certificate under that Act on the day immediately before the appointed day, and to whom clause (a) does not apply, and

(c) every dealer registered under the West Bengal Motor Spirit Sales Tax Act, 1974, (West Ben. Act XI of 1974) who is in possession of a registration certificate under that Act on the day immediately before the appointed day, and to whom clause (a) or clause (b) does not apply,

shall be liable to pay tax under this Act on all sales, other than those referred to in section 15, effected on or after the appointed day.

(2) Every dealer to whom sub-section (1) does not apply shall, if his gross turnover of sales calculated from the commencement of any year exceeds the taxable quantum at any time within such year, be liable to pay tax under this Act on all sales, other than those referred to in section 15, effected on and from the date immediately following the day on which such gross turnover of sales first exceeds the taxable quantum.

(3) In this Act the expression "taxable quantum" means,-

(a) in relation to any dealer who imports for sale any goods, other than those specified in Schedule IV, into West Bengal, 30,000 rupees ; or

(c) in relation to any dealer who manufactures or produces any goods, other than those specified in Schedule IV for sale, 1,00,000 rupees ; or

(e) in relation to any other dealer, 5,00,000 rupees, excluding turnover of sales of goods specified in Schedule IV.

(4) Every dealer who has become liable to pay tax under sub-section (1) or sub-section (2) shall continue to be so liable until the expiry of three consecutive years, during each of which his gross turnover of sales has failed to exceed the taxable quantum, and such further period after the date of such expiry as may be prescribed, and on the expiry of this later period his liability to pay tax under sub-section (1) or sub-section (2) shall cease.

EXPLANATION.- For the purposes of sub-section (4), in computing the period of three consecutive years in respect of a dealer who has become liable to pay tax under sub-section (1), the year or years which expired before the appointed day during which or each of which the gross turnover failed to exceed the taxable quantum referred to in the Bengal Finance (Sales Tax) Act, 1941, shall be included.

(5) Every dealer whose liability to pay tax under sub-section (1) or sub-section (2) has ceased under sub-section (4), shall, if his gross turnover of sales calculated from the commencement of any year again exceeds the taxable quantum at any time within such year, be liable to pay such tax on all sales, other than those referred to in section 15 effected on and from the date immediately following the day on which such gross turnover of sales again first exceeds the taxable quantum.

(6) The Commissioner shall, after making such enquiry as he may think necessary and after giving the dealer an opportunity of being heard, fix the date on and from which such dealer shall become liable to pay tax under sub-section (2) or sub-section (5).