(1)If any dealer fails to pay the tax due as required by sub-section (3) of section 21, he shall, in addition to the tax (including any penalty) due, be liable to pay simple interest on the amount so due at one per cent. per month from the date immediately following the last date for submission of the return under sub-section (2) of the said section for a period of one month, and at one and a half per cent. per month thereafter for so long as he continues to make default in such payment or till the date of completion of assessment under section 23, whichever is earlier.
