Beijing is experiencing its worst air pollution this year, with monitoring stations reporting exceptionally high levels of micro-pollutants, city officials have said.
The city reported levels of tiny PM2.5 particles in the air measuring more than 600 micrograms per cubic metre late on Monday – the safe level, according to the World Health Organization, is 25 micrograms per cubic metre averaged over 24 hours.
"I felt like my lungs were blocked," said Xu Pengfei, a security guard in downtown Beijing.
City authorities issued an orange alert, the second highest of four danger levels, and polluting factories were required to reduce production, as visibility fell and buildings receded into the thick smog.
Across the city people complained of an acrid, smoky odour and resorted to wearing tight-fitted face masks in an attempt to protect their lungs. However, such masks offer little protection from the tiny particles present in the air on days with heavy pollution.
"The air pollution is all-encompassing, and it requires both the government and individuals to shoulder the responsibility to clean up the air," said Liu Juntang, a businessman whose company develops environmental technology.
Beijing vowed to clean up its toxic air last year, after sales of air purifiers across the country skyrocketed as citizens attempted to protect themselves from increasing levels of pollution. .
The city got off to a good start this year, but a spate of unusually cold days and early snow in November prompted citizens to turn on their winter heating systems and bid farewell to blue skies as the notorious smog rolled in.
The air quality grew even worse on Friday and continued to deteriorate throughout the weekend, prompting the city government to issue an orange alert on Sunday. The highest, red, alert was only narrowly avoided, officials said, because the air quality is expected to improve by Wednesday.