An NRI, when returning to India, his or her residential status immediately changes to resident individual and he or she needs to change his or her status by informing the bank. NRO NRE and FCNR accounts is decided as per FEMA (Foreign Exchange Management Act) provisions.
So far as Income Tax provisions are concerned, residential status is governed under section 6 of The Income Tax Act, 1961.
The budget 2020 introduced a new regime under section 115BAC giving Individuals and HUF tax payers an option to pay income tax at lower rates. Starting from FY 2023-24, the new income tax regime will be set as the default option. If you want to continue using the old regime, you must submit a form at the time of return filing.
Read the complete article: Residential status and new tax regime