The pollution level in Beijing is at one of its highest ever

The reading given by the USA embassy dwarfs the maximum recommended by the World Health Organisation, which is just 25 micrograms per cubic metre Swathes of northern China were hit and levels in Jinan, a provincial capital hundreds of km away, reached over 400.

It comes as the Paris climate convention is attended by President Xi Jinping.

It also ordered all construction sites to stop work as well to cut emissions, after issuing an orange alert, the second-highest response to air pollution, the People’s Daily reported.

Environmental group Greenpeace said the pollution showed the “weakness” of Beijing’s air quality alert system.

Communist leaders have tightened emissions standards and are investing in solar, wind and other renewable energy.

China is estimated to have released between nine and 10 billion tonnes of carbon dioxide in 2013, almost twice as much as the United States and around two and a half times the European Union. Beijing has vowed to clean up its air and had been doing fairly well prior to this pollution event, with air generally cleaner than it was in 2014. Tests found the burning of coal to blame for most of the latest pollution surge, the official Xinhua News Agency said, citing Zhang Dawei, the head of Beijing’s environmental monitoring centre. His citizens have responded with a barrage of Weibo posts noting that, had the conference been held in the Chinese capital, the mission may have been treated more urgently. Authorities said they only avoided issuing the highest-level alert because conditions were forecast to improve by Wednesday. At least one primary school in Beijing canceled all classes on Tuesday.

Click ahead to see how air pollution created by 30 years of unchecked industrial activity has left Beijing under a dark and poisonous cloud.

Average PM2.5 concentrations in China’s major regions during peak heating times are about 20 percent higher than annual average levels, especially in the north, the ministry said on October 29.

Pollution in Beijing is notoriously bad, but Leavenworth says the past five days have been “dispiriting”. Certain sections on a highway outside the capital also had to be closed on account of the lack of visibility, the Transportation Ministry said.

Since then 23 cities in the Beijing-Tianjin-Hebei province region have recorded air quality readings of 200 and above, deemed as seriously or hazardously polluted.