Power to reduce or waive penalty: Commissioner may reduce or waive penalties subject to disclosure, cooperation, payment and approval requirements. Section 273A permits the Commissioner to reduce or waive certain penalties where the assessee voluntarily and in good faith discloses concealed or inaccurate particulars before detection, cooperates with enquiries, and has paid or arranged payment of tax and interest; larger cases require prior approval by senior authorities, relief is ordinarily once in a lifetime, and orders are final while interest in specified sections cannot be waived.