As per the Budget 2020 has introduced a New Income Tax Section 115 BAC for the Financial Year 2020-21, also the CBDT declare A Notification about this New Section that how to calculate your Income Tax under this Section. You can choose your option that you can get the Old Tax Regime or New Tax Regime. It also appears that if you choose the New Tax Regime, you can not availed any Income Tax benefits except the NPS benefits by the employer to the employees and no additional Tax Slab for the Senior Citizen in this New Tax Slab. But if you choose the Old Tax Regime you can get all benefits of all Income Tax Sections and you also availed the Old Income Tax Slab Rate as per the F.Y.2019-20. Then it is questioned how to choose the Tax Benefits, read the article How to Choose your Option New or Old Tax Regime.
As the Financial Year 2020-21 and Assessment Year 2021-22 has already started from 1st April 2020 which will be the end of 31st March 2021, So you can calculate for the Taxable Income for the Financial Year 2020-21. by the Income Tax Calculator for F.Y. 2020-21.
If you have got any Arrears Amount of Salary from the Previous Financial Years, you may obtain how to Relief from Tax through the Income Tax Arrears Relief Calculator U/s 89(1) and prepare the Form 10E From the Financial Year 2000-01 to Financial Year 2020-21 ( Updated Version)