; (iii) may be banked for application to compliance obligations in future compliance periods under CSAPR; and (iv) shall be surrendered upon the permanent cessation of operation of such coal refuse electric utility steam generating unit. (2) Other sources (A) No increase in overall State budget of sulfur dioxide allowance allocations For purposes of paragraph (1), the Administrator may not, for any compliance period under CSAPR, increase the total budget of sulfur dioxide allowance allocations for a State in which a unit described in paragraph (1)(A) is located. (B) Compliance periods 2017 through 2020 For any compliance period under CSAPR that commences on or after January 1, 2017, but before December 31, 2020, the Administrator shall carry out subparagraph (A) by proportionally reducing, as necessary, the unit-specific sulfur dioxide allowance allocations from each source that— (i) is located in a State in which a unit described in paragraph (1)(A) is located; (ii) permanently ceases operation, or converts its primary fuel source from coal to natural gas, prior to the relevant compliance period; and (iii) otherwise receives an allocation of sulfur dioxide allowances under CSAPR for such period. (c) Emission limitations To address hydrogen chloride and sulfur dioxide as hazardous air pollutants (1) Applicability For purposes of regulating emissions of hydrogen chloride or sulfur dioxide from a coal refuse electric utility steam generating unit under section 112 of the Clean Air Act ( 42 U.S.C. 7412 ), the Administrator— (A) shall authorize the operator of such unit to elect that such unit comply with either— (i) an emissions standard for emissions of hydrogen chloride that meets the requirements of paragraph (2); or (ii) an emission standard for emissions of sulfur dioxide that meets the requirements of paragraph (2)