Mexico City Smog Alert Forces New Curbs on Factories, Cars

Authorities Friday ordered more than 200 industries to slash operations by 50% to 75% and banned hundreds of thousands of cars from the roads to battle dangerously high ozone pollution levels.

Ozone levels by midday soared to more than three times the limit considered safe by the World Health Organization, continuing the smog-choked city’s worst environmental alert on record.

Mexico City Mayor Manuel Camacho Solis ordered 223 factories to slash their operations through Sunday and banned 600,000 cars from driving both today and Sunday.

It was the first time traffic restrictions, routinely applied during the workweek, were imposed on the weekend.

Levels of the colorless, odorless gas were measured at 356 points on a Mexican measure of pollution in the southwest of the city at midday. A reading of more than 100 is considered dangerous by WHO.

City authorities had already ordered a 30% cut in industrial activity, halved the number of government vehicles on the roads, suspended all paving and painting of streets and deployed special police units to keep traffic moving.

On Tuesday, authorities closed schools in the capital and banned more than a million vehicles when ozone reached a record high of almost 400 points. Schools were kept open Friday.

Ozone, formed by hydrocarbons and oxides of nitrogen in the presence of sunshine, can produce short-term irritation of the respiratory system and long-term lung damage, especially in the young.