CityLab: "The city of Madrid is poised to enact some of the toughest anti-pollution laws in the world. When air quality drops beneath a new threshold, Spain’s capital will banish half the city’s cars from inner Madrid and introduce strict speed limits on the beltway. In an unusual spirit of municipal largesse, it will also make public transit entirely free to use for the day. Laboring under a reputation as one of Europe’s most congested, polluted capitals, Madrid could finally be about to clean up its act."
