Advance tax deferment interest applies to instalment shortfalls, with staged rates and threshold-based exemptions. Interest is chargeable for deferment of advance tax where an assessee liable to pay advance tax fails to pay it, or pays less than the advance tax due on returned income by the specified instalment dates. The provision prescribes staged liability at 3% for shortfalls up to 15 June, 15 September and 15 December, and 1% for shortfall up to 15 March, with corresponding percentages of tax due on returned income set for each due date.