Beijing officials on Monday declared a red alert, which is the highest level of alarm for air pollution response in the Chinese capital. This morning schools were closed, as the Chinese government news agency Xinhua announced.   

The response system was announced in 2013, and this was the first time that a code red had been issued.
Under the code red, temporary restrictions say that all schools are required to close, cars can only drive on alternate days depending on license plate numbers, and outdoor barbecuing and fireworks are banned. The latter would, if carried out legally, affect the sale of the popular grilled-kebab street food.

The announcement arrived by the state news agency, Xinhua, which posted on its English-language Twitter account that the restrictions would be in effect, and included a photo of the Bird's Nest-the stadium built for the 2008 Summer Olympics-in dark smog and nearly invisible. The Beijing government's official website also posted advisories, according to the New York Times

An influx of toxic air was in northern China starting around Nov. 28. On Nov. 30, some parts of the city had air containing the poisonous particulate matter PM 2.5 at nearly 40 times the limit the World Health Organization recommends. This was the year's worst pollution, and it began dissipating on Dec. 1, with strong winds, as the Times reported.

The emergency system is intended to alert citizens at least 24 hours in advance of bad smog, based on wind and weather forecasts.

"This week in Paris, China is rightfully getting credit for its policies to tackle climate change," Alex Wang, a law professor at the University of California, Los Angeles, who studies Chinese environmental policy, said in the New York Times article. "But the extraordinary air pollution in Beijing right now demonstrates just how much remains to be done to make these policies work in practice."