A general view shows a building during high levels of pollution in Mexico City, Mexico, May 14, 2019. Picture taken through a glass window. REUTERS/Henry Romero
MEXICO CITY (Reuters) – Mexico authorities declared an environmental emergency on Tuesday for metropolitan Mexico City, one of the world’s most populous megalopolises, as smoke from nearby wildfires pushed pollution to levels deemed potentially harmful to human health.
Environmental authorities advised residents to avoid outdoor activities and exercise, remain indoors with windows and doors shut, and for especially sensitive groups, including infants, the elderly and sick, stay at home.
The city’s Environmental Commission of the Megalopolis came under pressure to act after visibility in the city began dropping sharply last week due to ash and smoke in the air. Dry weather has played a role in a spate of fires around the city.
Fine particulate matter known as PM2.5 hit 158 micrograms per cubic meter of air at the Nezahualcoyotl measuring station at 5 a.m. The World Health Organization recommends a daily mean air quality guideline below 25.
Annual averages above that amount are associated with higher long-term mortality risks. The world’s most polluted capital city, New Delhi, has an annual average of 113.5.
Mexico City’s air, once infamously lethal, saw a steady improvement through the late 1990s. In recent years however, there have been renewed signs of deterioration.
The environmental authority also asked residents and businesses to do their part in helping to reduce emissions, such as by using cars less, while authorities fight the numerous blazes raging in Mexico City and surrounding states.
Reporting by Anthony Esposito and Noe Torres; Writing by Frank Jack Daniel; Editing by Cynthia Osterman