Clifford Coonan Letter from BeijingAutumn traditionally is the most comfortable time of year in Beijing, when the city is transformed from the cauldron of summer into a pleasant and sunny metropolis.
People sit on chairs outside their houses chatting with neighbours, and take long walks in the imperial gardens of the Temple of Heaven.
These days it's getting harder to see the imposing outlines of the Forbidden City through the yellow-tinged smog choking the boulevards of the city and the sounds of autumn are the coughs and wheezes of Beijingers, suffocating on particle pollution as coal-fired power plants on the city outskirts start to crank up for the winter.
More than 400,000 people in China die prematurely from air pollution every year, according to the state environmental protection agency Sepa, the sorry by-product of a fast-growing economy. Yet these pollution levels could more than quadruple within 15 years if China does not curb its rapid growth in energy consumption and cool its love affair with the car.
There are 2.5 million cars on the streets of Beijing these days and the once omnipresent bikes are now considered a second-class mode of transport.
The eye-stinging sight of smog blocking the view of the Perfumed Hills in the distance is one of the more depressing vistas in the Chinese capital. There are days when doctors tell you, if you can avoid it, don't go out. And then there are days you pray for rain to come and dissipate the smog a little.
China is the world's second-biggest producer of greenhouse gas emissions and is expected to overtake the United States as the biggest.
Roughly a third of China is exposed to acid rain and about 70 per cent of the country's rivers and lakes are polluted.
Coal-fired power plants are still China's main source of energy and with the bitterly cold winter approaching, they are getting busy.
Last year, the emission of sulphur dioxide (SO2) in the country reached 26 million tonnes, ranking China highest in the world, causing about 30 per cent of the country's territory to be ravaged by acid rain.
New satellite images released by the European Space Agency show Beijing and the surrounding region of northeast China are the world's worst area for nitrogen dioxide pollution, which is produced by poorly filtered vehicle exhausts.
The World Bank, which says that 16 of the 20 most polluted cities in the world are in China, estimates that 400,000 people here die each year from air pollution-related illnesses, mainly lung and heart diseases.
The most polluted cities are in the northern and western areas of the country, including those in the coal- producing Shanxi province and cities surrounded by mountains. Which includes Beijing.
Other major contributors include the factories making the goods which underpin the country's economic boom and heavy industry is one of the worst offenders.
The 86-year-old Capital Iron and Steel Works, known as Shougang, lies just 17km outside the city and it produces 18,000 tonnes of breathable particles a year.
The government is keen to improve China's environmental record. President Hu Jintao regularly refers to "environmentally sustainable development" in speeches about harnessing economic growth to better distribute the new riches.
There are sound political reasons for improving the environment.
People all over the country staged mass demonstrations this summer over pollution, which is damaging their crops and affecting their children's health.
Next year, China will enact a law encouraging the use of renewable energy and it also has fuel efficiency rules, although sitting behind a truck belching black smoke it's hard to see who takes these rules very seriously.
Sepa is drafting a programme which will focus on emissions from the coal-fired power plants and it is also planning to keep a tight rein on construction projects that will make the problem worse.
The agency also plans to blacklist cities that fail to reach the national air quality standard.
"The list will be announced regularly to warn cities of deteriorating air quality," said Zhang Lijun, a senior official of Sepa.
The aim is to hit the polluters in their pockets.
Zhang said that as a penalty, Sepa would issue risk warnings to investors who considered investing in the cities that had been blacklisted for several consecutive years.
Air pollution, including dust, smog, acid rain and suspended particles, posed an increasingly dangerous threat to human health, said Zhang.
He said that if the air quality had been "good", more than 178,000 people every year would die of air pollution-related illnesses.
The Olympic Games in Beijing in 2008 are never far from any official's mind. Taxi drivers in the capital like to joke how there will be no pollution by the time the Games are under way.
"They'll shut the factories, give everyone a one-month holiday and no one will be the wiser," said one driver. "No problem."