The Indian Contract Act, 1872
60. Application of payment where debt to be discharged is not indicated-
Where the debtor has ommitted to intimate, and there are no other circumstances indicating to which debt the payment is to be applied, the creditor may apply it at his discretion to any lawful debt actually due and payable to him from the debtor, whether its recovery is or is not barred by the law in force for the time being as to the limitations of suits.