Government authorities in Mexico City, which is home to over 20 million people, have ordered hundreds of thousands of cars off the roads and offered free subway and bus rides as their air pollution alert stretched into a third day.
“Sadly, the air quality, particularly in the Valley of Mexico, has been badly deteriorating over the last months and years,” Mexican President Enrique Pena Nieto said at a public ceremony, referring to the region that surrounds the capital city.
“We need to go further, be braver and particularly be more determined to make sure that from now on, and over the next years, we avoid having a contaminated atmosphere that puts at risk the health of the people who live in this great megalopolis,” he added.
Mexico City lies in a high-altitude valley ringed by smog-trapping mountains.
Officials advised people to limit outdoor activity because of high ozone levels that were nearly double acceptable limits in the sprawling capital.
Ozone, which is a key ingredient of smog, is a form of oxygen created by the reaction of sunlight with air containing other pollutants such as hydrocarbons and nitrogen oxide. It can cause breathing difficulties and heart disease.
Environment Secretary Alejandro Pacchiano said if conditions don’t improve, further measures may be considered such as suspending industrial activity at factories.