JOIN USA swathe of China was blanketed with dangerous acrid smog today after levels of the most dangerous particulates reached around 50 times World Health Organisation maximums, with energy use for heating blamed as winter sets in.
Pictures showed smog so thick that buildings in Changchun, the capital of Jilin province in the northeast, were rendered invisible.
One image showed a restaurant's neon sign seemingly floating in mid-air above traffic, proclaiming in yellow: "Northeastern Dumpling King".
An image circulating online showed a man biking through snow in Shenyang, capital of the neighbouring province of Liaoning, yesterday wearing a vintage-looking gas mask, and the official news agency Xinhua quoted a hospital official in the city saying that his respiratory ward had been overwhelmed, with all its beds full.
Levels of PM2.5, the tiny airborne particles considered most harmful to health, reached 860 micrograms per cubic metre in Changchun, a city of around eight million, today.
The World Health Organisation's recommended maximum is a 24-hour average of 25 micrograms.
"Today's haze is pretty severe and choking - when I walked out the door I thought someone's house was on fire," said one poster in Changchun on China's Twitter-like Sina Weibo.
The Changchun city government said on social media it was initiating a "level three" emergency response, telling schools to stop organising outdoor activities, and reminding residents to stay indoors and "take health precautions", without further specifications.
China's chronic pollution problem has been linked to hundreds of thousands of premature deaths, and has become a major source of popular discontent with the government.
PM2.5 particulates can play a role in heart disease, stroke, and lung ailments such as emphysema and cancer.
Online commentators were furious.
"If heating companies dare to buy cheap, low-quality coal and pollute the environment, they should be discovered and immediately shot," said one poster.
Overall levels of PM2.5 particulates reached 1,157 micrograms per cubic metre in Shenyang yesterday, data from the city's own environmental protection bureau showed.
They peaked as high as 1,400 in parts of the city according to state broadcaster CCTV, with visibility less than 100 metres.
The readings appear to be among the highest ever publicly recorded in China.