(iii) Special rules For purposes of this subparagraph, the provisions of subparagraphs (B) and (C) of section 179A(b)(2) (as in effect before its repeal by Public Law 113–295) shall apply. (c) Clean-Burning fuel use credit (1) In general For purposes of subsection (a), the clean-burning fuel use credit is the amount equal to 50 cents for each gasoline gallon equivalent of clean-burning fuel used by an eligible business during the taxable year to propel qualified clean-fuel vehicle property. (2) Clean-burning fuel For purposes of paragraph (1), the term clean-burning fuel has the meaning given to such term by section 179A (as in effect before its repeal by Public Law 113–295), except that such term includes compressed natural gas and biodiesel (as defined by section 40A(d)(1)). (3) Gasoline gallon equivalent For purposes of paragraph (1), the term gasoline gallon equivalent means, with respect to any clean burning fuel, the amount (determined by the Secretary) of such fuel having a Btu content of 114,000. (d) Other definitions For purposes of this section— (1) Eligible business The term eligible business means— (A) a qualified business entity or a qualified proprietorship (as such terms are defined by section 1397C, determined by substituting nonattainment area for empowerment zone and enterprise zone each place it appears), and (B) a trade or business located outside of a nonattainment area, but only with respect to qualified clean-fuel vehicle property used substantially within a nonattainment area. (2) Nonattainment area The term nonattainment area shall have the meaning given to such term by section 171 of the Clean Air Act (42 U.S.C. 7501). (e) Denial of double benefit Except as provided in section 30B(d)(4), no credit shall be allowed under subsection (a) for any expense for which a deduction or credit is allowed under any other provision of this chapter. (f) Recapture The Secretary shall, by regulations, provide for recapturing the benefit under any credit allowable under subsection (a) with respect to any