As a number of cities try to clear the air, specialists in Beijing warn that the pollution and emergency responses to reduce it could damage the economy and tourism.
Authorities in the capital said on Monday they had ordered 58 factories with high emissions to suspend operations. Work at construction sites that could cause dust, such as leveling land, were also halted.
The city has advised young children and the elderly to stay indoors.
The capital has ordered kindergartens, primary and middle schools to scrap physical education classes until air quality improves.
Up to 30 percent of government vehicles have also been banned from the capital's roads on heavily polluted days, according to a spokesman for the Beijing Traffic Management Bureau.
By Saturday, official data showed the density of PM2.5 - particles of 2.5 microns or smaller that can damage the lungs - had reached 900 micrograms per cubic meter in several Beijing districts. It was the highest level recorded since authorities began releasing the data to the public in early 2012.
The safe daily level is 25 micrograms per cubic meter, according to the World Health Organization.
Coal emissions and vehicle exhaust fumes played a major role in the pollution and a low-pressure weather front trapped the polluted air.
Experts say the pollution and measures to reduce it have already hit the economy.
Officials at Monday's news conference declined to speculate on the financial repercussions of the smog.
However, Feng Yongfeng, founder of Green Beagle, an environmental protection NGO in the capital, said the emergency measures "will definitely set back construction on many projects". Although, he added, "it might be time for the city to slow down".
Zhang Hui, a professor of tourism from Beijing Jiaotong University, said the city's tourism will also be affected, as conditions put off visitors and residents from seeing the sights.
Questions:
1. How many factories have been ordered to suspend operations?
2. What is the safe daily level of PM2.5?
3. What factors have played a role in the smog?
Answers:
1. 58.
2. 25 micrograms per cubic meter.
3. Coal emissions, vehicle exhaust fumes and a low-pressure weather front.
(中国日报网英语点津 Helen 编辑)
About the broadcaster:
Emily Cheng is an editor at China Daily. She was born in Sydney, Australia and graduated from the University of Sydney with a degree in Media, English Literature and Politics. She has worked in the media industry since starting university and this is the third time she has settled abroad - she interned with a magazine in Hong Kong 2007 and studied at the University of Leeds in 2009.