(CBS News) BEIJING -- Scientists with the U.N. said on Wednesday that greenhouse gases, which influence climate change, have hit-- mostly because industry is ramping up in the developing world. Their report said "mankind has upset the natural balance of our atmosphere." What does this mean? We take a look at this in China.
There have been more smoggy days in China this year than any other in the last half-century.
The northern city of Harbin came to a standstill recently, when a thick layer of white smog choked the city. Air quality levels reached 40 times the safe limit recommended by the World Health Organization.
This week, China's ministry of environmental protection put out new guidelines. It said on the most hazardous days, public schools should be closed, workers should stay home, and outdoor activities stopped.
In China, monitoring pollution levels is as common as checking the temperature. Face masks and air purifiers are a regular sight.
On particularly polluted days, students at the International School of Beijing have recess inside a giant, air-purified dome. Parents told us the air filtration system was a key factor in choosing a school.
The air pollution is made worse by China's dependence on coal, which it consumes nearly half of the world's supply. In September, it said it would cut coal consumption and close heavy-polluting plants. And there's a ban on building new coal power plants in key industrial regions.
In Beijing, which already has more than 5 million cars on the road, the government plans to reduce the number of new cars that will be allowed next year by 40 percent.