According to Table F of the Companies Act, 2013 interest on calls in…

When any shareholder fails to pay the amount due on allotment or on any of the calls, such amount is known as ‘Calls in Arrears’/‘Unpaid Calls’. Calls in Arrears represent the debit balance of all the calls account. Such amount shall appear as ‘Note to Accounts. The Articles of Association of a company may empower the directors to charge interest at a stipulated rate on calls in arrears. If the articles are silent in this regard, the rule contained in Table F shall be applicable which states that the interest at a rate not exceeding 10% p.a. shall have to be paid on all unpaid amounts on shares for the period intervening between the day fixed for payment and the time of actual payment thereof.