Much of eastern China was choking under a thick blanket of yellow smog on Thursday, with schools closing and visibility down to just 500 meters amid widespread health concerns.
The foul-smelling smog began to thicken late on Wednesday, and readings of the smallest and most harmful form particulate matter, PM2.5, reached 300-500 micrograms per cubic meter, levels considered hazardous to health by international standards.
Authorities in the eastern city of Nanjing announced a code red pollution alert late on Wednesday, ordering schools and kindergartens to suspend class on Thursday.
Nanjing resident Sun Lin said the thickness of the smog was unprecedented in the city, where the sun was likened to the dark orange color of a "salted egg yolk," a traditional Chinese snack.
"It's just haze everywhere outside," Sun said. "A lot of people are wearing face masks outside. It seems that Nanjing has never known such a big smog before."
The Shanghai government issued a fresh orange code alert for smog at 5:00 p.m. on Thursday afternoon, advising people to reduce outdoor activities, the city's meteorological office reported on its official website.
Meteorological officials say the smog looks set to stay until Sunday, official media reported.
And in the eastern port city of Qingdao, which once enjoyed a reputation for clean air, the government announced an orange alert on Tuesday, suspending outdoor activities for schoolchildren.
Anger and fear
Netizens who took official advice to stay indoors took to social media sites to vent anger and fear of the effects of China's worsening air pollutants on their health.
"PM2.5 gets into your lungs, and at 0.3 micrometers it can get into the bloodstream," commented netizen @3904311699 on the popular news portal Sina.com.
"We don't know how long our lungs and blood can hold out," the user wrote. "We are living in a mega-haze, and lung cancer is on its way."
A netizen identified as @aiji, or "Egypt," said the air in China was already poison.
"If we were in any other country, they would be protesting in the streets by now, but we just suck it up like the submissive white bunnies that we are," the user wrote.
And a netizen from Yancheng in the eastern province of Jiangsu added: "The smog is so thick that I can't see the traffic lights clearly."
"I was following the car in front, but I was afraid the light would turn red and I'd be caught on the CCTV camera [at the intersection]," the user said.
Development at all costs
Fellow Jiangsu resident Bi Kang said he was angry at the ruling Chinese Communist Party for sacrificing the environment in favor of economic development at all costs.
"I didn't go out today, because I saw the smog was pretty bad; it's all grey and soupy, like a descending fog," Bi said.
"They have ruined the environment because they have pursued ... GDP growth without thinking about any of this."
Many netizens expressed similar views, with others wondering if the smog would extend across most of China.
Reaching South Korea
Smog from China reached the South Korean cities of Seoul and Incheon, spreading to North Chungcheong and Gangwon provinces by Tuesday afternoon.
Local media said the smog was found to contain heavy metals like arsenic and lead, the national daily Chosun Ilbo reported.
A U.S. environmental official said on Wednesday that the U.S. west coast has been affected by smog drifting across the Pacific Ocean from China.
South Korean media have also reported an impact on their country's environment from Chinese pollution.
Gina McCarthy, U.S. Environmental Protection Agency administrator, said mercury emitted in China had entered the upper atmosphere and had been deposited in U.S. rivers and streams.
Promises to reduce
Beijing has vowed to reduce its PM2.5 pollution index to a level similar to the U.S., and U.S. officials have said they will collaborate to help China reduce pollution using experience gained from their own pollution reduction efforts in the 1960s.
Environmental activist Song Xinzhou, who founded the nongovernmental group Green Beijing, said the Chinese government has failed to treat the country's environment as an interdependent system.
"The environment is a system that is everywhere, and [the smog] has spread gradually; it didn't move south all of a sudden," Song said.
"We have been destroying the environment for such a long time in this country."
Time for cleanup
Song said any cleanup attempts would take at least as long to work as the original damage had taken to do.
"Any measures aren't going to have any immediate effect; any environmental regeneration is going to take a very long time, and we are likely to see more serious smog incidents in the process," he said.
He said any cleanup process should take the public's right to be informed, and to supervise the government, into account.
"Nothing will change if they just arrest a few people," Song warned. "And any change isn't going to come quickly."
The Chinese government announced a serious of measures aimed at combating pollution, including the smog problem, which is known colloquially as "airpocalypse," earlier this year.
The coal industry, which supplies more than three-quarters of China's total electricity needs, in particular is being targeted as one of the dirtiest sectors.
Around 600 million people are affected by air pollution and smog days that plague northern China, according to a July report from China's State Development and Reform Commission.
And a recent report by the American National Academy of Sciences found that residents of northern China could be losing five years of life expectancy compared with those in the south, which until recently has enjoyed better air quality.
Reported by Xin Lin for RFA's Mandarin Service. Translated and written in English by Luisetta Mudie.