Tax exemption under Section 10(46) preserves specified income of a state electricity regulatory commission, subject to conditions. Notification under Section 10(46) exempts specified receipts of the Madhya Pradesh Electricity Regulatory Commission - including petition fees, interest on savings, fines and charges, and incidental receipts such as grants, sale of tender documents, processing and copying fees, license fee, vehicle rent, staff loan interest, RTI receipts and tariff book receipts - subject to conditions that the Commission not engage in commercial activity, that the nature of specified income remain unchanged, and that the Commission file returns as required under the Income-tax Act; the notification is given retrospective effect for listed years.