But it seems that nothing can stop the attacks of foul air that spoil the otherwise perfect picture. I wasn't in Shanghai during the worst attack last year. But my friends told me it was bad, so bad that some of them sent their children to stay with their grandparents in other cities for months on end.

Some other cities, including Hong Kong and some European cities, for instance, are trying to combat their respective air pollution problems by limiting the use of cars, especially during rush hours in the busiest commercial districts.

The Hong Kong government said that it is considering the introduction of a toll system requiring cars to pay a fee for the privilege of entering the city center during the morning and evening rush hours. This is a widely seen as a radical proposal because the free use of roads built with public funds has always been taken for granted by people in Hong Kong.

But the traffic congestion, which is blamed for being one of the causes of the worsening air pollution, has greatly softened public resistance to road tolls. More and more people are calling on the government to ban cars from the busiest streets in the most popular commercial districts.

Milan in Italy bans all cars from the roads in the city when the air pollution indicators exceed what is considered the acceptable level. And several other European cities have adopted similar, though less drastic, measures to clean up the air.

The Shanghai government is known for its determination and decisiveness when it comes to enhancing the city's image. Now is the time for swift action to combat smog, which is not only tarnishing Shanghai's image but, more importantly, threatening the health of its residents.

The author is a senior editor with China Daily, email: jamesleung@chinadaily.com.cn