15 states are suing over the Trump administration's delay of Obama-era air-quality standards -- Business Insider

Attorneys general from 15 states filed a legal challenge on Tuesday over the Trump administration's delay of Obama-era rules reducing emissions of smog-causing air pollutants. ..
http://www.businessinsider.com/ap-15-states-appeal-epa-delay-of-stricter-air-quality-standards-2017-8