Mexico City has declared a smog emergency, warning residents to avoid spending time outdoors.
From Mexico News Daily:
At least 23 fires were reported in Mexico City yesterday, affecting nearly all of the capital’s 16 boroughs and contributing to poor air quality.
To avoid possible respiratory ailments, the commission recommended that residents remain indoors with windows and doors shut, and avoid intense exercise or other outdoor recreational activities.
According to Wikipedia: “after loosening regulations in 2015 by the Mexico City government, air pollution has steadily increased in recent years in Greater Mexico City.”