In case a return has been declared invalid, it shall be deemed that no return has been filed by the taxpayer. In such a case, a new return can be furnished if the time limit for furnishing the original/belated return has not yet expired. If the time limit for furnishing the return has expired, you cannot file the return for such an assessment year. In that situation, the Assessing Officer can proceed to make the best judgment assessment under Section 144. Alternatively, you may approach the CBDT for condonation of delay in filing of return.