China has made tremendous progress in emission control for on-road vehicles (light duty vehicles, buses, and heavy-duty trucks) in recent decades. The vehicle population in China grew nearly sevenfold, from 16 million to 108 million, between 2000 and 2012, and this rapid pace will continue for the foreseeable future. Although the burgeoning vehicle market brings enormous environmental pressures, China has responded forcefully to mitigate the effects of adding these vehicles to its roads and highways. In less than 15 years, vehicle emission control standards in China have advanced to China 4/IV (equivalent to Euro 4/IV in the European Union), and the fuel quality standards have been tightened to 50 parts per million (ppm) maximum sulfur content. Despite these accomplishments, though, China’s air quality remains poor throughout the country. More must be done in all sectors to lower pollutant emissions., This report focuses on means of controlling vehicle tailpipe emissions in the transportation sector.