In response to rising air pollution that made Paris the most polluted city in the world for a brief time, Mayor Anne Hidalgo promoted the first World Car-Free Day a year ago. The city says last year’s first car free day helped reduce emissions and noise significantly. Nitrogen dioxide levels dropped even by half in the center according to air pollution monitors. Within two years the first Car-Free Days were organized in Reykjavík (Iceland), Bath (United Kingdom) and La Rochelle (France), and the informal World Car Free Days Consortium was organized in 1995 to support Car-Free Days worldwide. Since taking office in 2014, Paris Mayor Anne Hidalgo has made improving Paris’ air quality one of her top priorities.