The seventh proviso to section 139(1) provides for furnishing of return by a person referred to in clause (b) of the said sub-section (1), who is not required to furnish a return under the said sub-section, if such person has undertaken the following high value transactions during the previous year —
1. Deposit of Rs. 1 crore or more in current accounts
2. Expenditure on foreign travel for more than Rs. 2 Lakh
3. Expenditure on the consumption of electricity for more than Rs. 1 Lakh
Finance Act, 2019 has inserted a new seventh proviso to section 139(1) to provide for mandatory filing of return of income for undertaking certain high-value transactions even though the person is otherwise not required to file a return of income due to the fact that total income is below the basic exemption limit.
It's based on basic exemption limit i. e. 250000/-, 300000/-&500000/- According to respective age