law: 18. Transitional arrangements for input tax credit.
  (1) A registered person, other than a person opting to pay tax under section 10 of the Central Goods and Services Tax Act, shall be entitled to take, in his electronic credit ledger, credit of the amount of Value Added Tax and Entry Tax, if any, carried forward in the return relating to the period ending with the day immediately preceding the appointed day, furnished by him under the existing law, not later than ninety days after the said day, in such manner as may be prescribed:
  Provided that the registered person shall not be allowed to take credit in the following circumstances, namely:
  (i) where the said amount of credit is not admissible as input tax credit under this Act; or
  (ii) where he has not furnished all the returns required under the existing law for the period of six months immediately preceding the appointed day; or
  (iii) where the said amount of credit relates to goods sold under such exemption notifications as are notified by the Government:
  Provided further that so much of the said credit as is attributable to any claim related to section 3, sub-section (3) of section 5, section 6 or section 6A or sub-section (8) of section 8 of the Central Sales Tax Act, 1956 (74 of 1956) that is not substantiated in the manner, and within the period, prescribed in rule 12 of the Central Sales Tax (Registration and Turnover) Rules, 1957 shall not be eligible to be credited to the electronic credit ledger:
  Provided also that an amount equivalent to the credit specified in the second proviso shall be refunded under the existing law when the said claims are substantiated in the manner prescribed in rule 12 of the Central Sales Tax (Registration and Turnover) Rules, 1957.
  (2) A registered person, other than a person opting to pay tax under section 10 of the Central Goods and Services Tax Act, shall be entitled to take, in his electronic credit ledger, credit of the unavailed input tax credit in respect of capital goods, not carried forward in a return, furnished under the existing law by him, for the period ending with the day immediately preceding the appointed day in such manner as may be prescribed:
  Provided that the registered person shall not be allowed to take credit unless the said credit was admissible as input tax credit under the existing law and is also admissible as input tax credit under this Act.
  Explanation.
  For the purposes of this section, the expression "unavailed input tax credit" means the amount that remains after subtracting the amount of input tax credit already availed in respect of capital goods by the taxable person under the existing law from the aggregate amount of input tax credit to which the said person was entitled in respect of the said capital goods under the existing law.
  (3) A registered person, who was not liable to be registered under the existing law or who was engaged in the sale of exempted goods or tax free goods or goods which have suffered tax at first point of their sale in the Union territory and the subsequent sales of which are not subject to tax in the Union territory under the existing law but which are liable to tax under this Act or where the person was entitled to the credit of input tax at the time of sale of goods, shall be entitled to take, in his electronic credit ledger, credit of the value added tax and entry tax, if any, in respect of inputs held in stock and inputs contained in semi-finished or finished goods held in stock on the appointed day subject to the following conditions, namely:
  (i) such inputs or goods are used or intended to be used for making taxable supplies under this Act;
  (ii) the said registered person is eligible for input tax credit on such inputs under this Act;
  (iii) the said registered person is in possession of invoice or other prescribed documents evidencing payment of tax under the existing law in respect of such inputs; and
  (iv) such invoices or other prescribed documents were issued not earlier than twelve months immediately preceding the appointed day:
  Provided that where a registered person, other than a manufacturer or a supplier of services, is not in possession of an invoice or any other documents evidencing payment of tax in respect of inputs, then, such registered person shall, subject to such conditions, limitations and safeguards as may be prescribed, including that the said taxable person shall pass on the benefit of such credit by way of reduced prices to the recipient, be allowed to take credit at such rate and in such manner as may be prescribed.
  (4) A registered person, who was engaged in the sale of taxable goods as well as exempted goods or tax free goods under the existing law but which are liable to tax under this Act, shall be entitled to take, in his electronic credit ledger,
  (a) the amount of credit of the value added tax and entry tax, if any, carried forward in a return furnished under the existing law by him in accordance with the provisions of sub-section (1); and
  (b) the amount of credit of the value added tax and entry tax, if any, in respect of inputs held in stock and inputs contained in semi-finished or finished goods held in stock on the appointed day, relating to such exempted goods or tax free goods in accordance with the provisions of sub-section(3).
  (5) A registered person shall be entitled to take, in his electronic credit ledger, credit of value added tax and entry tax, if any, in respect of inputs received on or after the appointed day but the tax in respect of which has been paid by the supplier under the existing law, subject to the condition that the invoice or any other tax paying document of the same was recorded in the books of account of such person within a period of thirty days from the appointed day:
  Provided that the period of thirty days may, on sufficient cause being shown, be extended by the Commissioner for a further period not exceeding thirty days:
  Provided further that the said registered person shall furnish a statement, in such manner as may be prescribed, in respect of credit that has been taken under this sub-section.
  (6) A registered person, who was either paying tax at a fixed rate or paying a fixed amount in lieu of the tax payable under the existing law shall be entitled to take, in his electronic credit ledger, credit of value added tax in respect of inputs held in stock and inputs contained in semi-finished or finished goods held in stock on the appointed day subject to the following conditions, namely:
  (i) such inputs or goods are used or intended to be used for making taxable supplies under this Act;
  (ii) the said registered person is not paying tax under section 10 of the Central Goods and Services Tax Act;
  (iii) the said registered person is eligible for input tax credit on such inputs under this Act;
  (iv) the said registered person is in possession of invoice or other prescribed documents evidencing payment of tax under the existing law in respect of inputs; and
  (v) such invoices or other prescribed documents were issued not earlier than twelve months immediately preceding the appointed day.
  (7) The amount of credit under sub-sections (3), (4) and (6) shall be calculated in such manner as may be prescribed.