The morning commute on Day 1 of Mexico City's smog-alert car ban
{{#rendered}} {{/rendered}}Cars drive along what would usually be a very busy thoroughfare in Mexico City, Wednesday, April 6, 2016. City authorities have barred millions of vehicles from the streets due to a pollution alert. (AP Photo/Dario Lopez-Mills)
A man rides his bicycle along Reforma Avenue in Mexico City, Wednesday, April 6, 2016. City authorities have barred millions of vehicles from the streets due to a pollution alert. (AP Photo/Dario Lopez-Mills)
Passengers enter the Tasquena metro station in Mexico City, Wednesday, March 16, 2016. Authorities have banned more than 1 million cars from the roads and offered free subway and bus rides to coax people from their vehicles as Mexico City's first air pollution alert in 11 years stretched into a third day. (AP Photo/Eduardo Verdugo)
A woman uses a surgical mask to protect herself from the smog in Mexico City. (Photo: AP/Rebecca Blackwell)
Passengers enter the Tasquena metro station in Mexico City, Wednesday, March 16, 2016. Authorities have banned more than 1 million cars from the roads and offered free subway and bus rides to coax people from their vehicles as Mexico City's first air pollution alert in 11 years stretched into a third day. (AP Photo/Eduardo Verdugo)
A man walks over what would usually be a very busy thoroughfare in Mexico City, Wednesday, April 6, 2016. City authorities have barred millions of vehicles from the streets due to a pollution alert. (AP Photo/Dario Lopez-Mills)
Air pollution hangs over Mexico City, Wednesday, March 16, 2016. Authorities have banned more than 1 million cars from the roads and offered free subway and bus rides to coax people from their vehicles as Mexico City's first air pollution alert in 11 years stretched into a third day. (AP Photo/Eduardo Verdugo)