Customs exemption for imported steel used in fuel-efficient vehicle body panels, conditional on certification and use verification. Exemption under section 66 exempts imported steel sheets and blanks in Chapters 72 or 73 when used to manufacture body panels of fuel-efficient motor cars or vans (engine capacity not exceeding 1000 cc) from customs duty in excess of 25% ad valorem and from additional duty under section 3, subject to certificate-based approval by industrial authorities, post-import use verification by Central Excise, exclusion of waste from exemption with duty payable, prescribed fuel-efficiency testing protocols, and specified definitions; effective until 30 June 1987.