(iii) Sales to a registered dealer engaged in the business of raising coal, of any goods which are shown to the satisfaction of the Commissioner to be required directly for use in connection with the raising of coal; (iv) sales to any undertaking supplying electrical energy to the public under a licence or sanction granted or deemed to have been granted under the (IX of 1910) of goods for use by it in the generations distribution of such energy; (v) Sales of goods which are shown to the satisfaction of the Commissioner to have been dispatched by, or on behalf of dealer to an address outside the (Union Territory) of Delhi; (vi) such other sales as may be prescribed;" This was the definition until 28th May, 1972, when by Finance Act, 1972 the main enactment in section 5 (2) (a) (ii) was substituted by the following provision : "(2) In this Act the expression 'taxable turnover" means that part of a dealer 's gross turnover during any period which remains after deducting therefrom (a) his turnover during that period on (i) x x x (ii) sales to a registered dealer of goods of the class or classes specified in the certificate of registration of such dealer, as being intended for re sale by him, or "for use by him as raw materials in the manufacture in the Union Territory of Delhi (hereinafter in this subclause referred to as Delhi), of goods (other than goods declared tax free under section 6) (A) for sale inside Delhi; or (B) for sale in the course of inter State trade or commerce, being a sale occasioning or effected by transfer of documents of title to such goods during the movement of such goods from Delhi; or (C) for sale in the course of export outside India being a sale occasioning the movement of such goods from Delhi, or a sale effected by transfer of documents of title to such goods effected during the movement of such goods from Delhi, to a place outside India and after the goods have crossed the customs frontiers of India; and of containers or other materials for the packing of goods of the class or classes so specified for sale;" 105 Section 7, sub section (1) laid down that no dealer shall, while being liable to pay tax under section 4, carry on business as a dealer unless he has been registered and possesses a registration certificate and subsection (3) of that section provided for grant of a certificate of regis tration to a dealer on an application being made by him under subsection (2) and said that such certificate of registration shall specify the class or classes of goods for the purposes of sub clause (ii) it clause (a) of sub section (2) of section 5.