ELR Citation: 49 ELR 20162
No(s). 19-1019 (D.C. Cir. Oct 1, 2019)

The D.C. Circuit vacated EPA's 2018 update to the Cross-State Air Pollution Rule (CSAPR). States and environmental groups argued that EPA violated the CAA by failing to require upwind states to reduce their contribution of ozone precursors to downwind states in accordance with the deadline by which downwind states must comply with the ozone NAAQS. The court found that the update relied on an interpretation of the CAA's "good neighbor" provision that it had rejected in a prior case concerning the Agency's 2016 update to the CSAPR, and thus held that the update was invalid because of its failure to align the upwind states' and downwind states' respective deadlines. It therefore vacated the update.