In urban areas around the world, increasing motorization and growing travel demand make the urban transportation sector an ever-greater contributor to local air pollution and greenhouse gas emissions. The situation is particularly acute in developing countries, where growing metropolitan regions...

The decade from 2010 to 2019 marked a significant turning point in China's history of environmental regulation and pollution. This article describes the recent trends in air and water quality, with a focus on the five years since China declared a "war on pollution" in 2014. It summarizes the...