Section 11AA of the Central Excise Act, 1944, lays out the provisions for interest on delayed payment of duty. As per this section, any person who is liable to pay duty is also liable to pay interest on the unpaid amount at a rate specified by the Central Government. The interest rate is to be notified by the Central Government in the Official Gazette, and it is to be not less than 10% and not more than 36% per annum. The interest is to be calculated from the date on which the duty becomes due until the date of actual payment of the amount due.
However, there is a provision that states that no interest will be payable if the duty becomes payable due to an order, instruction, or direction by the Board under section 37B of the Central Excise Act, 1944, and the entire amount of duty is voluntarily paid within 45 days from the date of issue of such order, instruction or direction, without reserving any right to appeal against the said payment at any subsequent stage of such payment.