A federal appeals court has rejected a request from the Environmental Protection Agency to reconsider its August decisionto vacate a major air pollution rule.The Cross-State Air Pollution Rule is designed to reduce the amount of pollution that blows across state lines. It places limits on the sulfur dioxide and nitrogen oxides produced in 28 states, including Kentucky.The Environmental Protection Agency proposed CSAPR in response to a previous court ruling that the rule's predecessor--the Clean Air Interstate Rule--wasn't strict enough. But now the court has ruled twice that CSAPR is too aggressive, and that states weren't given enough deference in setting their emissions plans.From SNL Energy: The rejection of the CSAPR has been a thorn in the side of the EPA and states for other reasons, too. A number of downwind and upwind states had relied on emissions reductions under CSAPR to demonstrate attainment with ozone and particulate matter National Ambient Air Quality Standards, or NAAQS. The EPA had used anticipated CSAPR reductions to redesignate certain nonattainment areas as being in attainment with the 1997 ozone standard and the 1997 and 2006 PM 2.5, or fine particulate matter, standard. With that reliance no longer valid, states will have to make deeper reductions through alternative means to come into attainment by the deadlines, observers said. Still another issue that has emerged with the vacatur of CSAPR is the Regional Haze Rule, a regulation aimed at restoring natural visibility at national parks and wilderness areas through emission reductions at select older coal-fired power plants. The EPA finalized a rule allowing power plants participating in CSAPR's trading program to be shielded from pollution control retrofit obligations under the Regional Haze Rule, but with CSAPR's invalidation, state plans that now rely on CAIR are being litigated.The SNL article says it's unlikely the Supreme Court will take up the case, which will force the EPA to go back to the drawing board. The Clean Air Interstate Rule remains in effect until a new, more stringent regulation is approved.