The interest is payable under section 50, when tax liability of a previous tax period is discharged in a subsequent period. Accordingly, from the February 2026 tax period onwards, the GST portal auto-populates this liability breakup based on document dates reported in GSTR-1, GSTR-1A, or IFF where such supplies relate to earlier periods. Taxpayers are now required to mandatorily open this tab on the payment page and confirm the details by clicking “SAVE” (or edit, if necessary) before filing GSTR-3B.