Beijing issued its highest smog alert on 7 December, as pollution in the city is expected to remain at almost hazardous levels for a few days. It is the first time authorities in the Chinese capital have issued a red alert, which brings school closures as well as industrial and traffic.

The emergency measures will remain in place at least until 10 December at midday, the Beijing Municipal Environmental Protection Bureau said, adding it was to "protect public health and reduce levels of heavy air pollution."

Monitoring sites recorded pollutants filling the air at very unhealthy levels, more than 10 times higher than considered safe by the World Health Organization (WHO).

The US embassy reported a peak of 274 PM2.5 particles per cubic metre at 7pm on 7 December, just short of the hazardous threshold on its air quality index, which starts at 300. "Active children and adults, and people with respiratory disease, such as asthma, should avoid all outdoor exertion; everyone else, especially children, should limit outdoor exertion, "an embassy advice read.

The WHO deems a concentration of 25mg as safe. Readings are expected to continue rising until 11 December when a forecasted change in should bring some relief to local residents.

Meanwhile, motorists have been allowed to get behind the wheel only every other day, depending on their licence plate number. Heavy vehicles have been banned from circulating and extra public transport put in place.

Beijing has been attempting to reduce its pollution levels and so far in 2015, the situation had been better than the previous year. However the city has experienced extreme smog in recent weeks.

At the end of November, PM2.5 readings were as high as 976mg in some suburbs. On 30 November, the US embassy recorded 666mg of PM2.5. Despite the monster pollution, in that occasion authorities issued only an orange alert, the second highest in the four-tier scale, as skies were forecasted to clear before three days.

Beijing Smog
A man wearing a protective mask looks from inside a bus as Chinese artist Kong Ning walks in her costume made of hundreds of orange plastic blowing horns during her art performance raising awareness of the hazardous smog in a historical part of Beijing Reuters