Links between premature deaths and pollution are still being studied, Wu Wencong reports.

Among the world's best- known mega-cities, Beijing and Shanghai must be the only ones where house prices are still climbing rapidly, despite severe air pollution that will take years to solve.

But for people unhappy at becoming human vacuum cleaners in a polluted metropolis, and who are equally unwilling to forgo an urban lifestyle, which is the better choice - the capital city in the north, or the southern international trade center at the end of the Yangtze River?