BEIJING (Reuters] – Friday’s visibility in Beijing fell to 200 meters (219 yards), as heavy pollution engulfed the capital. Some highways were closed.

Beijing’s first warning about severe pollution for autumn and winter was issued on Thursday. This required that some outdoor activities and factory operations were stopped and schools closed.

The haze has made visibility difficult as the tallest buildings in the city have disappeared.

The heavily industrialised Beijing-Tianjin-Hebei region often suffers from heavy smog in the fall and winter, especially on days without wind.

It is likely that the polluting elements will disperse due to a cold wind from Siberia arriving over the weekend.

According to the China Environment Ministry, China intends to reduce concentrations of dangerous, tiny airborne particles called PM2.5 in major cities by an average of 4 percent per year this winter.

According to U.S. Embassy Beijing, the PM2.5 levels in urban areas rose as high as 234 micrograms/cubic meter on Friday. This indicates very unhealthy indoor air.

The ministry announced in September that China will wage its overall winter campaign against pollution in 64 cities in the industrialised and smog-prone northern regions.

China will host the Winter Olympics from Beijing on February 4-20.