Beijing, Dec 21.- Residents of more than 24 Chinese cities, mainly in the north and center of the country, today saw their usual life hit, for the five days in a row, by a dense and toxic fog covering vast areas of the territory.
This Wednesday several provinces in northern China continued under the harmful effects of a thick smog despite the emergency measures taken by the authorities that implemented a red alert since last Saturday.
The red alert, the maximum warning on the four-color scale used by this country for extreme weather conditions, is issued when the air quality index (AQI) is expected to exceed 200 micrograms for more than Four consecutive days, 300 for more than two days or 500 for at least 24 hours.
In this regard, primary and secondary schools are closed down, factories cease operations, construction works are halted and the circulation of cars on alternate days is applied according to their license plates.
However, the AQI in an industrial district of the city of Tangshanen, in Hebei, was still at a maximum of 578 this morning.
According to the World Health Organization, 24-hour exposure to concentrations of more than 25 micrograms per cubic meter is considered hazardous to humans while the recommended safety level of PM2.5 is 10 micrograms per cubic meter.