06 April 2018
U need permission from ur AO for that, after which u may b allowed to file the returns for the related years (after proper justification).
06 April 2018
You cant file return for upto A.Y. 2017-18 as the date for same is over. Even if you want to file then you can made an application for condonation of delay.
Such an application will be examined for acceptance/ rejection by the authority, based on the following criteria: a) The claim is correct and genuine; b) There is a case of genuine hardship on merits; c) Income is not assessable in the hands of any other person under the Income-tax Act; d) The refund has arisen as a result of excess tax deducted or tax collected at source, advance tax or self-assessment tax.