BEIJING -- Air pollution data from the Chinese government show that more than 90 percent of 360 Chinese cities failed to meet national air-quality standards in the first three months of the year, according to a report released Tuesday by Greenpeace East Asia.
Interior provinces were found to have the most polluted cities during those months. Cities near the eastern and southern coasts also had dire levels of fine pollutants, but the levels were lower than in the same period a year ago, the report said. The drop could be due to central government policies announced in late 2013 aimed at limiting coal use in China's most densely populated regions.
Researchers at Greenpeace East Asia, which is based in Beijing, ranked 360 cities after looking at levels of fine particulate matter called PM 2.5, considered more dangerous than other forms of pollutants because it can penetrate deep into the lungs and enter the bloodstream.
Air monitors in 367 Chinese cities record the levels of PM 2.5 and other kinds of pollutants hourly, and the data were released with the approval of the Ministry of Environmental Protection. Greenpeace said it discarded flawed data from seven cities.
The average concentration of PM 2.5 in the 360 cities was 66 micrograms per cubic meter, nearly twice the national standard of 35 micrograms per cubic meter. The average was more than 2½ times the more rigorous exposure limit recommended by the World Health Organization. That limit is 25 micrograms per cubic meter over a 24-hour period.
Only 32 cities met the national air-quality standard, while 141 cities, or nearly 40 percent, had PM 2.5 levels that were more than twice the standard.
The most polluted provinces were Henan, Hubei and Hebei. Beijing was the fourth-most-polluted, and Shandong, on the east coast, was fifth. All of those areas have or are surrounded by heavy industrial factories that rely on burning coal. Vehicle exhaust also contributes to pollution.
The three most polluted cities were Baoding, a steel town in Hebei; Kashgar, a traditional Silk Road oasis town in the far western region of Xinjiang; and Xingtai, another industrial town in Hebei. The three cleanest cities were all in the far west: Linzhi in Tibet, Lijiang in Yunnan province and Altay in Xinjiang.
The data show that China, despite a recent drop in the growth rate of coal use, continues to have cities with air that is among the most polluted in the world, alongside urban centers in India and Iran.
Communist Party leaders are aware that the environmental degradation is a major source of anxiety and discontent among ordinary Chinese. Li Keqiang, the prime minister, promised in March 2014 to carry out a "war against pollution," a vow that he reiterated last month.
Yet some party officials are reluctant to allow the wider public too much of a say in how that war should be waged, as evidenced by the government ban of a hugely popular online video documentary on air pollution, Under the Dome, that was carried on many Chinese websites for a week in early March.
Zhang Kai, a researcher and clean-air advocate at Greenpeace East Asia who helped oversee the report, said in an email that there was some positive news in the data. He said Greenpeace believes policies the central government announced in September 2013 to limit coal use in three major population centers led to notable drops in PM 2.5 levels in those areas.
Beijing, for example, had a nearly 13 percent drop in PM 2.5 concentration levels from the same three-month period in 2014. The average level in Beijing was 92.4 micrograms per cubic meter -- still nearly four times the recommended limit set by the WHO.
Zhang said Hebei overall had a 31 percent improvement in average PM 2.5 concentration, although, like Beijing, the level was still very high.
Information for this article was contributed by Mia Li of The New York Times.
A Section on 04/22/2015