(1) Every dealer liable to pay tax under section 10 or section 14 or sub- section (3) of section 27C, and registered under section 24 shall, in addition to the tax payable under any other provisions of this Act, be liable to pay tax on all his purchases in West Bengal from any person, whether a dealer or not, after deducting therefrom –

(a) purchases of goods, sales of which are declared tax free under section 21;

(b) purchases which are shown to the satisfaction of the Commissioner to have taken place in the course of inter-State trade or commerce within the meaning of section 3 of the Central Sales Tax Act, 1956 or in the course of import of goods into, or export of the goods out of the territory of India within the meaning of section 5 of that Act;

(c) purchases of goods which are shown to the satisfaction of the Commissioner to have been made from a registered dealer in West Bengal;

(d) purchases of goods which are shown to the satisfaction of the Commissioner to have been made from a dealer in West Bengal who has applied for registration within thirty days of his incurring liability to pay tax under sub- section (2) of section 23 and who has issued a tax invoice:

Provided that where the application for registration of the dealer has been rejected, no deduction shall be allowed on such purchases, from the date of order of rejection of the application;

(e) such other purchases as may be prescribed.

(2) The burden of proving that any purchase effected by a dealer is not liable to tax under sub-section (1) shall lie on such dealer.