The deadline for filing income tax returns (ITR) has passed, but taxpayers get one more chance: the tax department is allowing belated ITR filing up to December 31. Late filers will have to pay a penalty under Section 234F — ₹1,000 if annual income is up to ₹5 lakh and ₹5,000 if it exceeds that. In addition to the fine, interest will be charged on outstanding tax at 1% per month under Section 234A, calculated from the original due date until the return filing date. Taxpayers who have already filed can correct mistakes by submitting revised returns — this facility is also available until December 31 and can be used multiple times without extra penalty. If December 31 is missed, the only remaining route is an updated return (ITR-U), which can be filed within the allowed assessment period (up to 48 months) but may attract higher charges. Officials warn that late filing can also affect options like loss carry-forward and certain regime choices, so taxpayers are advised to file as soon as possible and verify returns within 30 days.