Mexico City authorities declared a Phase 1 air quality emergency on Wednesday morning, restricting vehicular traffic, including taxis and cargo deliveries. 

The Environmental Commission of the Megalopolis (CAMe) released a press bulletin at 3 p.m. confirming the measures will continue into Thursday for the fourth consecutive day, outlining the driving restrictions imposed when a Phase 1 air pollution emergency is declared.

During a Phase 1 emergency, automobiles with specific license plates and specific exhaust verification ratings are prohibited from driving, 50% of gas delivery trucks are kept off the road, and cargo trucks are only allowed to make deliveries between 6-10 a.m. Taxis can operate freely from 5 a.m. to 10 a.m. but thereafter they must adhere to restrictions linked to their license plates and exhaust verification ratings.

Authorities also urged residents to stay indoors and to avoid outdoor activities and exercise between 1 p.m. and 7 p.m. to prevent unnecessary exposure to high ozone levels. The CAMe also encouraged organizations to cancel civic, cultural and recreational activities that had been scheduled to take place outdoors.

According to the Mexico City Air Quality Monitoring System (SIMAT) a high-pressure system above the central and southern regions of the country has been creating conditions that make dispersion of pollutants difficult.

SIMAT also reported that only three of its 15 monitoring stations rated air quality in the Valley of Mexico as Good. Four others rated the air quality as Acceptable. The remaining eight rated it as Bad.

Conagua, however, is predicting that the Valley of Mexico, as well as the state of Querétaro and Morelos, could be seeing a bit of relief later on Wednesday, with intermittent rain squalls predicted thanks to humidity from the Pacific Ocean and the Gulf of Mexico.

With reports from La Jornada and Expansión