Living with bouts of choking, stewlike smog is a reality in Mexico City—which declared an environmental emergency this spring for air contamination—and Paris, now experimenting with a weekday driving ban for pre-1997 cars. But a breath of fresh air might be coming as these places, along with Madrid and Athens, have agreed to eliminate soot-spewing diesel vehicles from their roads by 2025.
Mayors from the four cities made the ambitious commitment Thursday at the C40 climate conference in Mexico City. Their hope is to cut down on outdoor air pollution, which the WHO estimates caused 3 million premature deaths in 2012, mostly in cities. Aside from banning diesel, the cities also vowed to create incentives for less-polluting vehicles and get more people using their pedestrian and cycling infrastructure.