A local policeman chats with a driver in a car with an even-number registration plate during a control at an access into Madrid, Spain, on December 29. Madrid has banned even-number plates from running on odd-number of days and vice versa in the city as a measure to improve air quality after meters showed alarming NO2 levels. The city is on level 3 protocol a day after the City Council banned cars from parking in downtown and reduced speed limit down to 70 km/hr on the city's bypass. EPA/Juan Carlos Hidalgo