Mr Tien said Mr Tsang had recently cited results of a government survey to show people cared more about the economy than democracy.

But he attacked Mr Tsang for failing to highlight at the same time people's concerns over air quality, which ranked third on the list of 25 issues polled by the Central Policy Unit.

Mr Tien conceded that the city had treated the pollution problem seriously in the past but said more needed to be done.

'What is clear is that the measures taken so far have failed ... If Mr Tsang is to fulfil his pledge to listen and to respond, he must convey a sense of urgency in dealing with the issue.'

Mr Tien also criticised Hong Kong's two power companies, saying it was disappointing to hear that their target for reducing pollutants by 2010 might be delayed by a year or two.

'How can anyone take the Hong Kong government seriously when it presses Guangdong to achieve a target that it cannot even get its own power companies to agree to?' he asked. He called for more stringent vehicle emission and fuel standards across the region.

'These are matters that must be approached not with trepidation and political pussy-footing, but with determination and resolve that the grave concern of Hong Kong people merits,' he said.

Emily Lau Wai-hing, vice-chairman of Legco's environmental affairs panel, issued a letter to Hong Kong General Chamber of Commerce chief executive Eden Woon Yi-teng yesterday, hoping he would promote environmental protection among businessmen investing in mainland factories.

She said factories in the Pearl River Delta, many of which are owned by Hong Kong businessmen, were the source of the city's air pollution.

Ms Lau hoped the business community would send representatives to discuss cross-border pollution at a Legco meeting scheduled for the end of next month.