North Carolina v. EPA, Cause No. 05-1244 (D.C. Cir., Jul. 11, 2005). On July 11, the D.C. Circuit Court of Appeals vacated EPA’s 2005 Clean Air Interstate Rule (“CAIR”), EPA’s rule addressing the Clean Air Act’s requirement that states implement SIPs that would prohibit significant contributions to NAAQS non-attainment areas in other states. CAIR regulated emissions of SOx and NOx, pollutant linked to acid rain and smog. It covered 28 states in the eastern half of the country and was primarily designed to address eastward-blowing power plant emissions. The D.C. Circuit took issue with several aspects of CAIR, including EPA’s decision to take a regional—rather than state-specific—approach in assessing NOx and SOx emissions budgets, and in CAIR’s provision for interstate emissions trading. Rather than remanding the rule for EPA to fix, the court vacated the rule after it determined that very little would survive the remand.