Tax exemption for regulatory authority income applies subject to non-commercial activity, unchanged income sources, and prescribed return filing compliance. Tax exemption is notified for the specified income of the Fees Regulating Authority under the repealed Income-tax Act, 1961, preserved through transitional provisions of the Income-tax Act, 2025. Exempt income includes institutional processing fees, interest, penalties and charges, government reimbursements and grants, and interest from deposits and investments. The Authority must not engage in commercial activity, must keep its activities and income nature unchanged, and must file the prescribed income-tax return. Non-compliance may attract penal action and withdrawal of exemption.