For those who are not responsible for tax audit, the deadline for submission is 31 August after the end of the financial year (Reduced return can be completed by 31 March subject to penalties) For persons responsible for tax audit and all other tests such as company, LLP or firm jointly, the deadline is 30 September after the end of the financial year. For FY 2017-18, this deadline has been extended from 30 September 2018 to 31 October 2018.
Non-payment of refunds - Any losses incurred during the year will not be processed further if the refund is completed after the due date for the return of the income tax return.
And a fine of Rs. 5000 under section 271F may be charged by the inspector.