Beijing woke on the first morning of the New Year covered in thick toxic fog, with a concentration of harmful particles 20 times higher than international standards.
After a long period of pollution in December, the Chinese capital was again smothered Sunday in an acrid grey haze which limited visibility to a few hundred metres.
Luminous signs on top of the skyscrapers seemed to float in the fog, while some tourists wore respiratory masks.
Levels of PM 2.5 — microscopic particles harmful to human health — exceeded 500 on Sunday morning, according to US Embassy estimates, vastly above the maximum threshold of 25 recommended by the World Health Organization (WHO) for a 24-hour exposure.
On Sunday the exasperation of people in Beijing overwhelmed social networks.
"Why didn't they trigger the red alert? Because it would be a bad omen for the first day of the year?" wrote a surfer on the Weibo microblogging platform.