Two Chinese businessmen walk into an international airport smoking room crowded with Western men puffing on cigars. The two Chinese are about to light up when one suit-wearing smoker turns and barks: "Do you mind?"
This is an old analogy used to illustrate the hypocrisy of some in the West who blame China for the world's pollution woes.
They blame China as it quickly develops to provide its citizens with a better quality of life. But developed countries are "developed" because their factories have been polluting the sky for more than 200 years.
Critics still blame China as it builds new cities with modern homes, running water, sewage systems, transport infrastructure, schools and hospitals, just as their countries did.
They blame China as it serves the needs of hundreds of millions of farmers moving from the land to the cities in the biggest urbanization program in human history. No nation has ever had to do this before, and the challenges are highly complicated.
Communities are like three-legged tables, held up by environmental, social and economic supports. The three are closely linked and affect the stability of the community.
The rampant rise in dirty factories fueled by economic development not only pollutes the air and waterways but also creates ghettos crammed with factory workers and the resulting social problems.
If one table leg is longer than the others, the table is unbalanced and society is far from harmonious.
US Secretary of State Hillary Clinton told China Daily last month her country and Europe "didn't know any better" about protecting the environment during their industrialization and development, and urged the Chinese not to make the same mistakes they did.
The Chinese people, from the Environment Minister down to grass-roots citizens, know change must come. And they are learning from their own mistakes, too.
After people protested over work on a $1.4 billion chemical factory near Xiamen, Fujian province, the project was halted and the local environmental agency was planning to review a proposal to relocate the plant to a neighboring city.
Deputy Environment Minister Zhang Lijun recently admitted serious problems remained in China and that local governments were not putting enough pressure on businesses to control pollution. His ministry is powerful and environmental laws have been toughened, but enforcement still relies on local officials and not enough has been done to fix China's air, lakes and rivers.
Local officials face a conflict of interest because heavily polluting industries offer more jobs and more taxes, which allow local governments to improve their regions - but at what cost?
A report from Zhang's department revealed nearly a quarter of the monitoring stations along China's major rivers found water quality was "worse" than ever, while another survey of five cities said the average air quality in two ranged from "polluted" to "hazardous".
London's Great Smog of 1952 is an extreme example of how this situation can go from bad to worse. More than 12,000 Londoners died as a result of the five-day catastrophe. The city's undertakers ran out coffins and it forced the British government to pass the original Clean Air Act.
This is a tragedy no nation wants to repeat.
Patrick Whiteley is a senior editor with China Daily