On February 3, Asahi Shimbun, Japan's leading daily newspaper, reported that, according to a survey conducted by a company in the environmental industry, breathing air in Beijing on a day with heavy smog is the same as smoking 21 cigarettes. The survey results were published by Xinmin Weekly, a magazine based out of Shanghai. The survey used air quality data collected from monitoring equipment owned by the Yuanda Group, a company that operates windmills and other facilities in China. According to the survey, which was conducted in several cities, breathing in the high levels of air pollution for one day was similar to smoking 21 cigarettes in Beijing, 25 in Guangzhou, 9 in Shanghai, 9 in Nanjing, 13 in Changsha, 12 in Chengdu and 13 in Wuhan. According to a Tsinghua University professor, whenever the Air Quality Index for PM 2.5 concentration hits 300, it’s like smoking 20 cigarettes that day. In Beijing, there were 15 such days in January alone.