Local coal-burning power stations and diesel-powered buses are also major contributors to the poor air quality that business leaders have said deters foreign investment and expatriates. But Gore said pollution is a problem not solely for the city but the world.

"There is a global problem in which the same activities cause the air pollution that Hong Kong experiences...All these activities cause global warming also," he told reporters.

"But it happens to every nation. Every nation must be a part of the solution, including China.

"The wealthier industrial countries that have done the most to create the problem should go first and begin to solve the crisis," he said, also calling on China, India and other developing economies to make efforts.

"There is no doubt that the climate crisis is the most serious crisis we have ever faced in the history of human civilization," he added.

A recent World Bank report said industrialised nations led by the United States continued to be the worst offenders for emissions of carbon dioxide (CO2).

But developing nations, particularly China and India, are producing an ever-greater share of CO2 emissions and so contributing to the trapping of heat-retaining gases in the Earth's atmosphere.

The report found both countries helped to drive up global greenhouse gas emissions by 15 percent over 1992-2002, fuelling the effects of climate change.

China, which is already the second largest polluter behind the US, increased its emissions by 33 percent between 1992 and 2002. India's emissions grew 57 percent in the same period.

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