A stagnant weather pattern combined with high levels of factory pollution and car exhaust has led to extremely dangerous air quality levels for one of the world's most populated cities.
Shanghai, home to more than 23 million people, was forced to take action on Friday as the concentration of harmful PM 2.5 particles reached 602.5 micrograms per cubic meter, according to the Associated Press.
This level well exceeds the World Health Organizations safety guideline set at 25 micrograms.
A couple in protective masks walk under haze in Shanghai, China, Friday, Dec. 6, 2013. (AP Photo/Eugene Hoshiko)
In reaction to these high levels of air pollution, schools were closed and children were told to stay indoors. The city also halted construction projects and reduced the number of government vehicles on the road.
The air quality level reached on Friday is the highest since the city began recording the data in December 2012.
A large area of high pressure centered over the city is leading to a stagnant air mass over the region allowing the air pollution to build up.
No changes in the weather pattern are expected through Sunday, likely leading to continued dangerous smog for Shanghai and surrounding areas.
A cold front will then press through the region on Monday leading to an increase winds throughout the atmosphere which should help reduce pollution levels.
A new storm will spread a swath of snow and sleet spanning more than 1,500 miles from northern Texas and Oklahoma to southeastern New York state and Massachusetts, during Wednesday into Thursday.
A potent storm will slam Italy and the Balkan Peninsula with heavy snow, flooding rain and gusty winds for the second half of this week.
A wide-reaching winter storm will stretch from Texas to New York Wednesday night and unleash heavy snow, ice and flooding rain along its path.
A change in the weather pattern will turn off arctic air invasions and allow the March sun to go to work over much of the Central and Northeastern United States next week.
A Turkish Airlines jet skidded off a runway as it attempted to land in Kathmandu, Nepal, amid dense fog early Wednesday morning.
People across the Midwest and Northeast will be bundling up as the first week of March comes to a close due to a southward push of arctic air.
Mauna Kea & Mauna Loa, HI (1990)
Heaviest snow on the tops of the Hawaiian volcanoes in 15 years. Snow drifted 6-10 feet.
New England (1717)
"The Great Snow" - 4 storms within a period of 10 days (from Feb 27 to March 7) that deposited about 36" in Boston area and about 48" to the north. Travelling or rural churchgoing was impossible for three weeks. Sheep were buried alive for 30 days.
Washington, DC (1909)
President Taft was inaugurated during a furious storm; 9.8" of wet snow disrupted travel and communications. The snow equalled 2.90" of water in 24 hours.