Citizens will have to pay fines to submit tax returns after the new deadline, NBR spokesman Syed A Mu'men said on Monday.
The previous deadline for tax filings was set to end on Nov 30 but the authorities decided to push it forward with "the convenience of taxpayers" in mind, the NBR spokesman said.
The NBR has not organised tax fairs this year due to the coronavirus pandemic.
The authorities are providing extensive services to the taxpayers throughout November at zonal offices.
Usually, the taxpayers can access all types of services at a single place when an income tax fair is held. The NBR had organised month-long income tax fairs for nine years to 2019. It cancelled the fairs in 2020 due to the pandemic.