Interest on delayed tax payment must be paid at government notified rates; higher notified interest applies to undue input credit or output reductions. Every person liable to pay tax must pay interest on any tax unpaid for the period it remains unpaid at a government notified rate within the statutory ceiling, calculated from the day after the tax was due; undue or excess claims of input tax credit or undue or excess reductions in output tax liability attract interest on the amount of such claim or reduction at a higher government notified rate within the separate statutory cap.