Most of Chinese cities failed to meet national air quality standards although noticeable environmental improvements have been achieved last year, according to the annual bulletin about the national environmental situation.
A report, released by the Ministry of Environmental Protection, presents an overview of the nation's environmental status - from air, water and ocean quality to farmland and forest coverage, noise and even background radiation.
It showed a general improvement in air quality last year with 74 major cities cut their levels of PM2.5 by 14.1 %, PM 10 by 11.4 % and sulfur dioxide by 21.9 % year-on-year.
Of the 338 monitored cities, 21.6 % met national air quality standards last year, rising from 9.9% in 2014, the bulletin said.
Xia Guang, director of the ministry's Policy Research Center for Environment and Economy, credited national campaigns for the improvements, saying in a report on China Central Television that "the action plan against air pollution works".
Still, the report found that 265 of the 338 monitored cities failed to meet national air quality standards.
Experts said that's because pollution control initiatives were complicated by thorny issues related to ozone at ground level.
Ground-level ozone pollution has popped into public view, the report said, especially in the Bejing-Tianjin-Hebei region, where 7 of 11 cities saw average ozone concentrations higher than national standards last year.