As thick smog rolling in from southern China blanketed Hong Kong on Monday, November 3, 2003, alarm bells rang. Said a spokeswoman for the city's Environment Protection Department, "Our advice is to reduce physical exertions and outdoor activities, especially for people with existing heart or respiratory illnesses.'

The pollution is believed to have come from factories and power plants in the heavily industrialised southern region of China bordering Hong Kong. Sarah Liao, secretary for the environment, transport and works, said it was a "regional problem'.

So it was that all China's first astronaut Yang Liwei, in the city on a 5-day tour, could see of Hong Kong's famous skyline was brown haze.