The city's environment department announced on Saturday that the air pollution index in the city had reached "Silk Cut" level, higher than the previous "Marlboro Lights". The Bureau of Environment Statistics took the unusual step of measuring air pollution via comparisons to cigarette brands after Shanghai's air pollution levels "fell off the scale" of more conventional systems.

Mr Li, the bureau chief, explained: "The elevation of the warning scale to 'Silk Cut' indicates that a ten minute walk in central Puxi now has the same effect on your lungs as smoking a pack of 'Silk Cut' cigarettes. We are confident that the air quality measures we are introducing will prevent us reaching 'Benson and Hedges' levels during 2008.

The tobacco firms could not be reached for comment, though they are thought to be unhappy at the competition in China's emerging market. "After all," commented one industry insider to Shangzilla, "if the Chinese can damage their lungs just by going about their everyday business, why do they need to take up smoking?"