The Central Board of Direct Taxes has said on July 31, 2017, that even if you have filed your ITR on or before the deadline of August 5, you will not get your income tax return unless and until you link your Aadhaar with PAN card.

People who have applied for Aadhaar card and have not received it yet, they can produce the acknowledgement number of their Aadhaar card application.

If in case you are not able to link your Aadhaar with PAN today i.e August 31, it will be considered as you have not filed your current financial year's (2016-2017) returns. The ITR filed would not hold any meaning and become useless. And then you may have to face the consequences for not filing the ITR as applicable. Like if the ITR is not processed, you will not get the refunds credited in your bank account.

You can check online whether your Aadhaar number is linked with PAN or not, you can simply login your account on the income tax department's e-filing website, here: https://incometaxindiaefiling.gov.in/. After you login, you have to search for 'Profile Setting' tab and click on the same to check if your PAN and Aadhaar is linked there.