China tries to clear the skies of smog by closing factories and limit cars on the road. A team of researchers from Peking University took air samples in 189 cities. The researchers found that the level of pollution exceeded many times over.

Beijing issued its first red alert for pollution this year, with very high levels of smog in Northern China. While the study does not investigate the causes of pollution, increasing production to compensate for economic losses. In 2014, Internet users coined the term "APEC blue". Clear skies in the capital was for two weeks during a gathering of world leaders during the APEC summit. The blue skies disappeared as soon as the leaders left.

Last year, azure sky during a military parade in September to celebrate the end of the Second world war was nicknamed "the blue parade" at the beginning of this year and ahead to the G20 in Hangzhou in August of this year, 225 plants were ordered to close and half of the cars in the city removed from the roads.

From December 2013 to March 2016, the researchers used the official air quality index (AQI) and measured the concentration of six pollutants, including PM2.5 and PM10, the most dangerous types of particles. The study showed the mean reduction during the local "two sessions" and 8.2% after sessions, compared with average levels.
sections: Society