4/6/2016 The Wall Street Journal
MEXICO CITY—Mexico City authorities have doubled down on the capital’s emergency driving ban, ordering two out of every five private vehicles to stay off the road Wednesday as heavy smog continued to blanket the megalopolis.
Mexico City has struggled since mid-March to contain high levels of ozone, which has risen well above maximum levels recommended by the World Health Organization, prompting the city to declare its first pollution emergencies in more than a decade. High levels of ozone contribute to respiratory problems such as asthma.
Cars are blamed for emitting 90% of the pollutants that led to the ozone buildup. The Environmental Commission for the Megalopolis estimates there are 10 million vehicles in the metropolitan area, where more than 20 million people reside. The area includes the Mexican capital and surrounding suburbs.