Income Tax Return relates to a specific tax year. A tax year is a period of twelve months ending on 30th day of June i.e. the financial year and is denoted by the calendar year in which the said date falls. For example tax year 2017, covers a period from 1st July 2016 to 30th June 2017.
Tax year includes special tax year, which means any period of twelve months and is denoted by the calendar year relevant to the normal tax year in which closing date of the special tax year falls. For example, tax year for the period of twelve months from January 01, 2016 to December 31, 2016 shall be denoted by calendar year 2017 and the period of twelve months from October 01, 2016 to September 30, 2017 shall be denoted by calendar year 2018.