Residents of Beijing wear masks in an attempt to protect themselves from air pollution in the city.
Air quality was below national standards in almost all China's major cities last year, a top environment official said on Saturday, after Premier Li Keqiang pledged to "declare war" on pollution.
Only three out of the 74 cities monitored by the government met a new air quality standard, said Wu Xiaoqing, a vice-minister of environment protection.
The standard lists limits on a string of pollutants, including sulphur dioxide, nitrogen dioxide and airborne particles.
It caps the average 24-hour exposure to PM 2.5 – small particles that easily penetrate the lungs and have been linked to hundreds of thousands of premature deaths – at 75 micrograms per cubic metre for residential areas, three times the World Health Organisation's recommended safe limit.
Even so, the only major cities to meet the standard were Tibetan capital Lhasa, Haikou on the southern island province of Hainan and Zhoushan on the coast of Zhejiang, Wu said.
'Lingering smog'
"The lingering smog again showed that our country's air pollution is extraordinarily severe," he told reporters on the sidelines of the annual session of the National People's Congress (NPC), China's Communist Party-led Parliament.
"Emissions of those pollutants were so huge they went beyond the level the environment can bear," he said.
China's heavy and chemical industries, its reliance on coal as its main energy source, rapidly growing car emissions and widespread urban construction were the main causes, he added.
Emissions in the Beijing-Tianjin-Hebei area in northern China, the Yangtze River delta in the east and the Pearl River delta in the south were five times the national average, Wu said.
The three regions account for 8% of China's land area, but use up 43% of the nation's overall coal consumption and produce 30% of its major pollutants, he said.
Industrial pollution
The Chinese public have been increasingly angered by the severe environmental consequences of the country's rapid industrialisation, among them smog, land laden with heavy metals and chemically contaminated waterways.
Li said in his speech to the NPC on Wednesday that the government would "declare war" on pollution as he sought to address the worries.
The government will shut down 50 000 small coal-fired furnaces this year, clean up major coal-burning power plants and remove six million high-emission vehicles from the roads, he said.
A cap will be put on the country's overall energy consumption, he said, without giving a figure.
Chinese authorities have repeatedly pledged action to improve the environment in recent months, but experts warn that implementation will be key. – Sapa-AFP