Income-tax is levied on the annual income of a taxpayer. The year under the Income-tax Law is the period starting from 01 April and ending on 31 March of the next calendar year. The Income-tax Law classifies the year as (1) Previous year and (2) Assessment year.
The year in which income is earned is called as previous year and the year in which the income is charged to tax or is assessed is called the assessment year. For example, income earned during the period of 01 April 2019 to 31 March 2020 is treated as income of the previous year 2019-20. Income of the previous year 2019-20 will be charged to tax in the next year, i.e., in the assessment year 2020-21.