Due date to file belated Income tax return with reduced penalty is 31st December of the Assessment year for FY ended on last 31st March.
FOr FY 2021-22, for reduced penalty of belated return is to be filed upto 31st December 2022.
FOr FY 2022-23, for reduced penalty of belated return is to be filed upto 31st December 2023.
FOr FY 2023-24, for reduced penalty of belated return is to be filed upto 31st December 2024.
Click below link for more detail:-
various due dates of Income tax for FY 21-22 (AY 22-23)
various due dates of Income tax for FY 22-23 (AY 23-24)
various due dates of Income tax for FY 23-24 (AY 24-25)