WildEarth Guardians v. McCarthy

摘要

Environmental groups were not entitled to bring Clean Air Act citizen suit claim against Environmental Protection Agency for failure to perform alleged mandatory duty under Section 166(a) of act to issue new prevention of significant deterioration regulations for ozone after national ambient air quality standards for ozone were revised, because: (1) citizen suit claims may only be brought against EPA to enforce performance of nondiscretion-ary duties; (2) nondiscretionary duties must be clear-cut or readily ascertainable from text of statute; and (3) even though under Section 166(a) EPA has nondiscretionary duty to issue PSD regulations after promulgation of NAAQSs, Section 166(a) is ambiguous as to whether EPA has nondiscretionary duty to issue PSD regulations after revision of NAAQSs and ambiguity precludes finding of nondiscretionary duty.