Air pollution

FILE – In this June 26, 2018 file photo, a Nissan Leaf charges at a recharge station while parked by the Denver City County Building in downtown Denver. The Colorado Air Quality Control Commission approved a new regulation on Friday, Aug. 16, 2019, requiring that at least 5% of the vehicles sold in the state by 2023 emit zero pollution. The rule approved Friday by the state Air Quality Control Commission applies to auto manufactures, not buyers. It's intended to boost the number of electric vehicles in a state struggling to control air pollution in heavily populated areas. (AP Photo/David Zalubowski, File)

FILE - In this Thursday, May 16, 2019 photo cars for export and import are stored in front of containers at the harbor in Bremerhaven, Germany. The German economy shrank by 0.1 percent in the second quarter as global trade conflicts and troubles in the auto industry weighed on Europe's largest economy. (AP Photo/Martin Meissner, file)

FILE - In this July 27, 2018, file photo, the Dave Johnson coal-fired power plant is silhouetted against the morning sun in Glenrock, Wyo. A coalition of 22 Democratic-led states has sued the Trump administration over its decision to ease restrictions on coal-fired power plants. The lawsuit, filed in the U.S. Court of Appeals for the District of Columbia Circuit, says the new rule violates the federal Clean Air Act because it does not meaningfully replace power plants' greenhouse gas emissions. (AP Photo/J. David Ake, File)

FILE - In this July 25, 2019, file photo, the sun sets in Cuggiono near Milan, Italy. A new U.N. report on warming and land use says climate change is hitting us where it counts: the stomach. The scientific report on Thursday, Aug. 8, finds that as the world warms it degrades the land more. (AP Photo/Luca Bruno, File)

FILE - In this June 26, 2019, file photo, a man adds fuel to his vehicle at a gas station in Orlando, Fla. A coalition of states is suing the Trump administration for the second time to block a planned reduction in penalties automakers pay when they fail to meet fuel economy standards. Twelve states and the District of Columbia sued the administration Friday, Aug. 2, 2019, for replacing an Obama-era regulation that imposed a penalty of $14 for every tenth of a mile-per-gallon that an automaker falls below the standards. (AP Photo/John Raoux, File)

In this photo taken on Friday, July 26, 2019, Greta Thunberg stands next to Swedish parliament in Stockholm. Thunberg, the Swedish teenager whose social media-savvy brand of eco-activism has inspired tens of thousands of students in Europe to skip classes and protest for faster action against climate change, said Monday, July 29, 2019 that she plans to take her message to America the old-fashioned way: by boat. (AP Photo/David Keyton)