China's top negotiator at international climate talks said on Tuesday that air pollution in his own country -- the world's biggest carbon emitter -- is harming its citizens.

"China indeed is suffering from severe air pollution," said Xie Zhenhua, vice chairman of the National Development and Reform Commission, the top economic planning body.

Smoggy conditions have "now become the norm which has severely affected the mental and physical health of the Chinese people", he added -- but voiced hope for improvement in the next decade.

Xie, speaking to reporters before global climate talks in Poland next week, attributed China's air problems to the country's "obsolete development model", its "unreasonable industrial and energy structure" and discharge of pollutants by some companies "in a very extensive way".

The root cause, he added, is the "use of fossil fuels".

Pollution is becoming a major source of public anger in China, and authorities vowed in September to reduce levels of atmospheric pollutants in Beijing and other major cities by as much as 25 percent by 2017 to try to improve their dire air quality.

The government said pollution levels would be cut by slowing the growth of coal consumption so that its share of China's energy sources fell to 65 percent by 2017.

China is the world's biggest coal consumer and is forecast to account for more than half of global demand next year.

Xie said that "in about five to 10 years we will see improvements in our air quality."

Chinese cities have been hit by intense air pollution in recent years, much of it caused by emissions from coal-burning power stations. Levels of small particles known as PM2.5 have reached as high as 40 times World Health Organisation limits this year.

Pollution, which tends to worsen as winter approaches, is also blamed on rapid urbanisation, dramatic economic development and climatic factors.

The bad air has tarnished the image of Chinese cities including Beijing, which saw an almost 15 percent drop in tourist visits during the first half of this year.

Air pollution contributed to 1.2 million premature deaths and 25 million healthy years of life lost in China in 2010, the US-based Health Effects Institute said in March.

The populous northeastern city of Harbin was shrouded in thick smog for several days late last month, with schools and a regional airport shut and poor visibility forcing some ground transport to a halt.

Xie stressed that China remains a "developing country", saying it has only recently reached a per capita GDP of $6,000 and still has about 90 million people living below the poverty line.

"China is also in the process of industrialisation, urbanisation and agricultural modernisation, so we are still in an uphill process," he said, adding: "We face daunting difficulties and challenges ahead."