text: "Passenger cars are responsible for 12 percent of greenhouse gas emissions in Europe...and up to 50 percent in some car-intensive areas in the United States. (paragraph 5)" Cars are the number one cause of pollution in most cities, espcially ones that have large amounts of drivers on the road in a single day. The author of source one, states in pargraph 8 that "..some new suburbs may well look more Vauban-like not only in developed countries, but also in the developing world, where emissons from an increasing number of private cars owned by the burgeoning middle class are choking cities"  All authors state that limiting car usage, is a great way to reduce air pollution. Paragraph 10, of source two, states that "After days of near-record pollution, Paris enforced a partial driving ban to clear the air of the global city" If car usuage was limited in cities there would be less smog, and pollution in the air. Not only would it be better for the enviroment, it would also be better for your health.