Rule 39
Tax Deduction Allowed
(1) Any registered person may, in the following circumstances, deduct the tax paid while importing or receiving his taxable goods or services in or before that month from the tax collected in supplying any goods or services:-
(a) Where the goods or services in respect of which tax deduction has been claimed are directly related
with the taxable business.
(b) If internally purchased, where tax invoice as referred to in Rule 17 has been obtained.
(c) If imported, where there are documents relating to import proving payment of tax while importing.
Explanation: “Documents relating to import”, for purpose of this Clause, means the customs declaration form, cash receipt, invoice of the goods and such other documents pertaining thereto as may be prescribed by the Department from time to time.
(2) In deducting tax pursuant to this Rule, it shall be deducted for only one time. In so deducting tax, one has to hold the invoice or documents relating to import as at One year before the date of claim for such tax deduction.
(3) In submitting the tax return for each tax period, registered person has to pay to the Tax Office such amount, along with the tax return, as may remain balance from deducting the tax paid while purchasing or importing the goods from the tax collected by him while selling the goods.
(4) If the amount of tax paid by a registered person in purchasing or importing exceeds the amount collected by him/her in selling, such excess amount may be deducted in other tax period. If such amount that can be so deducted in other tax period remains dues for a continuous period of Six months, he has to make an application to the Tax Officer in the format as referred to in Schedule -14 to get its refund in lump sum.
(5) If a registered person exports more than Fifty percent of his/her total monthly sale carried out in any month, he has to make an application, accompanied also by necessary documents related with the export, to the Tax Officer in the format as referred to in Schedule-15 to get refund of the deductible tax which has became excess for that
month. Upon receipt of such application the Tax Officer has to return the remaining tax pursuant to Rule 45. In making decision to so return the remaining tax, the Tax Officer has to pay attention to the following matters :-
(a) Where tax has been paid on purchase or import or not.
(b) Whether the tax return required to be submitted previously has been submitted or not; and if so submitted whether the claim for refund of tax is substantiated from such tax return of not.
Explanation: “Documents related with export”, for purposes of this Clause, means, in the case of  export except exchange of goods, export certificate, certificate of receipt of goods, payment certificate, letter of credit, certificate of origin, and such other documents related therewith as may be specified by the Department from time to time, and in the case of exchange of goods, means import declaration form instead of payment certificate.