Cities need to put efforts to deal with pollution and clear the air. Chinese cities will need to put efforts to clear up the sky when a new department to improve regional air quality is set up by 2015, according to the latest plan released by the State Council. Besides the existing pollution control program for SO2, regional emission caps   for other certain chemicals will be established in the three key air polluting areas-- the Yangtze River Delta, Pearl River Delta and the Beijing-Tianjin-Hebei region. Coal-consumption caps will also be tried out in some areas, according to the plan. "The plan is aimed at dealing with regional air pollution--such as acid rain and smog--which have become increasingly obvious in China in recent years and caused a severe threat to people's health," Zhang Lijun, vice-minister of environmental protection, said in an interview on Monday. "The air quality in a city affects the regions nearby because pollutants   Can travel through the atmosphere," said Chai Fahe, vice-director of Chinese Research Academy of Environmental Sciences. "So efforts to reduce air pollution in a single city, targeting a certain pollutant will not be enough," Chai said. Zhang said, "The country's major industrial districts--the Yangtze River Delta, Pearl River Delta and the Beijing-Tianjin-Hebei region--have recorded more than 100 misty days annually in recent years." These three regions, home to at least 200 million people, occupy only 6. 3 percent of the country's area but consume 40 percent of the country's coal and produce half of its steel, according to official figures. Studies also show that the visibility   in eastern regions of China has dropped by 7 to 15 km compared to that in the early 1960s, as a result of air pollution. Liaoning province, the Shandong Peninsula, Wuhan in Hubei province and its surrounding area, the Changsha-Zhuzhou-Xiangtan region in Hunan province, the Chengdu-Chongqing region, and the western coast of the Taiwan Straits are also listed as areas to carry out such regional air pollution control programs, according to the plan. The new plan also requires an improved air quality system, which will measure the pollution levels. "The current system, which only measures some major pollutants, cannot reflect ." said Chai. . Suppose the visibility in eastern regions of China was 130 km in the early 1960s, the visibility there nowadays is    _    .
123 to 115 km 137 to 145 km 123 to 145 km 115 to 137 km