Tax rate amendment for petroleum operations permits reduced tax on mutilated non serviceable goods upon authorised certification. The amendment adds petroleum and coal bed methane operations under HELP or OALP to the rate notification and provides that where goods are disposed of in non serviceable form after mutilation the recipient or transferee may, at his option, pay tax at a reduced rate provided he produces before the competent tax officer a certificate from a duly authorised hydrocarbon officer confirming the goods are non serviceable and were mutilated before disposal; the notification is effective retrospectively.