New York v. U.S. Environmental Protection Agency

In 1977, Congress amended the Clean Air Act (“CAA” or “the Act”) to strengthen the safeguards that protect the nation’s air quality. Among other things, these amendments directed that major stationary sources undertaking modifications must obtain preconstruction permits, as must major new sources, through a process known as “New Source Review” (“NSR”). According to a preexisting definition referenced in the 1977 amendments, a source undertakes a modification when “any physical change ... or change in the method of operation ... which increases the amount of any air pollutant emitted by such…