BEIJING, Mar 15 (AFP) — Beijing was cloaked by a thick yellow smog on Monday with pollution surging to hazardous levels as a sandstorm swept across China's capital.

City residents used goggles, masks and hair nets to protect themselves from  the choking air, with landmarks including the Forbidden City and the distinctive headquarters of state broadcaster CCTV partly obscured behind an apocalyptic-looking pall of smog.

The city government ordered all schools to cancel outside sport and events and advised those with respiratory diseases to stay inside. 

The poor air quality was due to a sandstorm from northern Mongolia, carried south by the wind and reducing visibility in Beijing to less than 1,000 metres (3,300 feet), state media reported.

Discussion of the orange haze lit up online discussions — with more than 54 million views on social media platform Weibo by Monday morning. Some users said the air was reminiscent of the apocalyptic science fiction film "Interstellar."

"This orange red sandstorm makes it looks like the end of the world," said one Weibo user.

Pollution in the city was at "hazardous" levels, according to air quality monitoring website Aqicn.

It said levels of PM 10 large particulate matter were nearly 20 times the World Health Organization's recommended daily maximum exposure.

Smaller PM 2.5 particles, which seep deep into human lungs and cause respiratory illnesses, were also at a hazardous level of 567 on Monday — more than 20 times the WHO recommended daily limit.

China cut its national average level of airborne PM 2.5 dramatically between 2015 and 2019 and the government has announced an ambitious target to reach carbon neutrality by 2060.