The EPA is extending by six months the deadline for taking final action on the petition that the District of Columbia has submitted to require EPA to make findings that sources upwind of the District of Columbia contribute significantly to its ozone nonattainment problems. Under the Clean Air Act (CAA or Act), EPA is authorized to grant this time extension if EPA determines that the extension is necessary, among other things, to meet the purposes of the Act's rulemaking requirements. By this document, EPA is making that determination.