The Supreme Court has upheld EPA regulations requiring reductions in SO2, NOx, and fine particle emissions in 28 states stretching from Texas to New York. The regulations, known as the “Cross-State Air Pollution Rule” or “Transport Rule,” are intended to reduce interstate transport of air pollutants, and were enacted under the “Good Neighbor Provision” of the Clean Air Act, which requires states implementing federal Clean Air Act requirements to enact measures to avoid...