Concessional GST rate for petroleum supplies subject to DGH certification and specific transfer and disposal conditions. A concessional central GST regime caps central tax on listed goods supplied for petroleum and coal bed methane operations under specified licences or contracts, contingent on production of a Directorate General of Hydrocarbons certificate to the proper tax authority at the time of outward supply; sub-contractors must furnish affidavit and undertakings, transfers require DGH transfer certificates and undertakings, and disposals are regularised by tax on depreciated value or, for mutilated goods, by paying tax on transaction value with DGH certification.