Shanghai Smog

Shanghai's iconic skyline has been slowly disappearing all week, cloaked by a thick acrid haze of smog. Reports of heavy pollution have circulated since Monday, but levels hit a new high on Friday.

The unprecedented air pollution made it hard for residents to breathe and even see. Authorities halted construction sites and all sporting events, ordered schoolchildren to stay indoors and pulled 30% of government vehicles from the roads. The city's air quality level exceeded the maximum of 500, its highest since the city started reporting pollution data. A level of 300 is considered severely polluted.

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"I feel like I'm living in clouds of smog," Zheng Qiaoyun, a local resident, told the Associated Press. "I have a headache, I'm coughing, and it's hard to breathe on my way to my office."

The city's concentration of PM 2.5 particulates, a pollutant that can have health risks when in high concentrations, rose to 602.5 micrograms per cubic meter on Friday. That's 24 times higher than the World Health Organization's safety guideline of 25 micrograms.

These extreme levels of air pollution were created by burning coal, emissions from vehicles and industries, and unusual weather patterns. The results are apocalyptic scenes of an almost invisible city. We collected some of the most shocking pictures below.

Image: ChinaFotoPress/ChinaFotoPress via Getty Images