Where a dealer makes sales of sugar, imported from outside the territory of India, in West Bengal, during the period commencing from the 1st day of January, 2010 ending on the 31st day of March, 2012, such dealer may, for the purpose of determination of his turnover of sales on which tax is payable, deduct under clause (c) of sub-section (1) of section 16, from his turnover of sales that part of turnover of sales which represents the sales of such sugar and he shall, on demand by the appropriate authority under the Act, furnish the relevant tax invoice or invoice or cash memo or bill and other related documents evidencing such sales of such sugar and also the documents evidencing that sugar sold by him was that which was imported from outside the territory of India:

Provided that no such deduction shall be allowed unless the dealer selling such sugar, on demand by the appropriate authority under the Act, furnishes the relevant tax invoice or invoice or cash memo or bill and other related documents, evidencing sales of sugar, imported from outside the territory of India, in West Bengal during the period mentioned above.