The due date to file ITR for AY 2020-21 is 10th January. The usual due date stands extended due to the outbreak of the pandemic COVID-19. However, in case you have balance tax payable above Rs 1 lakh, you should pay by 31 July 2020. A failure to pay by that date makes you liable for penal interest at 1% per month. The penal interest is in addition to interest liabilities if any on your tax payable.