Section 50 of the CGST Act : Interest on delayed payment of tax—
(1) Every person who is liable to pay tax in accordance with the provisions of this Act or the rules made thereunder, but fails to pay the tax or any part thereof to the Government within the period prescribed, shall for the period for which the tax or any part thereof remains unpaid, pay, on his own, interest at such rate, not exceeding eighteen per cent., as may be notified by the Government on the recommendations of the Council:
Provided that the interest on tax payable in respect of supplies made during a tax period and declared in the return for the said period furnished after the due date in accordance with the provisions of section 39, except where such return is furnished after commencement of any proceedings under section 73 or section 74 in respect of the said period, shall be payable on that portion of the tax which is paid by debiting the electronic cash ledger.
(2) The interest under sub-section (1) shall be calculated, in such manner as may be prescribed, from the day succeeding the day on which such tax was due to be paid.
(3) A taxable person who makes an undue or excess claim of input tax credit under sub-section (10) of section 42 or undue or excess reduction in output tax liability under sub-section (10) of section 43, shall pay interest on such undue or excess claim or on such undue or excess reduction, as the case may be, at such rate not exceeding twenty four per cent., as may be notified by the Government on the recommendations of the Council.