It is understandably confusing, because the Supreme Court also ruled that it is the case in 2007: https://en.wikipedia.org/wiki/Massachusetts_v._EPA https://en.

It is understandably confusing, because the Supreme Court also ruled that it is the case in 2007: https://en.wikipedia.org/wiki/Massachusetts_v._EPA https://en.wikipedia.org/wiki/Massachusetts_v._EPA. > greenhouse gases fit well within the CAA's capacious definition of air pollutant - United States Supreme Court