China has ordered thousands of factories to stay shut as it continues to struggle with smog at least 24 times recommended levels. Many schools have also been ordered to keep students indoors.
According to Tuesday's state-run "China Daily" newspaper, authorities in Beijing have ordered the closure of 2,100 highly polluting industries, while other factories were instructed to reduce work significantly. Citizens were also advised to stay indoors if possible, while airlines cancelled over 30 flights from Beijing and Shanghai, many to highly polluted Shaanxi province.
Layers of thick haze reduced visibility across the city of 20 million residents to merely several hundred meters (yards) and left a bitter odor, forcing people to resort to wearing face masks outdoors. Certain sections on a highway outside the capital also had to be closed on account of the lack of visibility, the Transportation Ministry said.
Schools were told to keep children indoors all day, while one particular school had to close for the day.
Residents were asked to stay indoors if at all possible, with many defying the recommendation and wearing face masks to filter at least some of the pollutants from the air
The city on Sunday issued the first orange alert in almost two years, the second highest warning level. The situation was particularly dangerous in southern Beijing, where airborne particles smaller than PM2.5, which means 2.5 microns in diameter, were measured at up to 900 micrograms per cubic meter - 35 times the recommended level. Just outside the capital, readings for PM2.5 were was as high as 976 micrograms per cubic meter in the suburban region of Liulihe.
The World Health Organization (WHO) recommends a maximum concentration 25 micrograms of the harmful microscopic particles per cubic meter to avoid serious damage to lung tissue.
Air quality had started deteriorating on November 27, and authorities said that they only narrowly managed to avoid having to issue the highest-level alert because conditions had been forecast to improve.
China's cities, following decades of economic growth and a widespread surge in car ownership, rate among the world's dirtiest urban areas. The country is also estimated to have released between up to 10 billion tonnes of carbon dioxide in 2013 alone, which is almost twice as much as the United States and around two and a half times the level emitted by the European Union.
Climate conference in Paris
The environmental alert coincided with Chinese President Xi Jinping attending the climate conference in Paris, aimed at limiting the effects of climate change.
Xi vowed to take "action" on reducing greenhouse emissions, while stressing that he did not believe in poor nations having to sacrifice economic growth in order to curb their greenhouse gasses. But the acute spike in pollution in parts of China casts a shadow over his actual commitment.
Communist leaders have tightened emissions standards over the years and are increasingly investing in renewable sources of energy, but China continues to depend chiefly on coal for at least 60 percent of its power. Most of the smog and pollution originates from coal-burning plants, which peak during the winter on account of heating households in addition to providing electricity.
China's state news agency Xinhua said tests confirmed that the majority of the latest spike in pollution came from coal burning. It cited an official as saying that cold weather conditions had trapped the pollutants closer to the ground.
Beijing pledged last year that carbon dioxide output would peak by "around 2030" - suggesting a decade and a half of growing emissions.
ss/tj (AFP, AP, dpa)