Guo Weiqi, an official with the municipal management committee, said in a phone interview that there are still at least 5,000 small-sized boilers using coal for heating in the city.

"All boilers will use clean fuel in 2008 as planned," he added.

Burning coal for heating in the winter has long been a problem since it causes serious air pollution.

Before 1997, Beijing consumed 28 million tons of coal each year, which produced 90 percent of the sulphur dioxide and 50 percent of the floating particles in the air, according to official statistics.

The municipal government has required all eight of Beijing's urban districts to use cleaner fuel to ensure a green Olympics in 2008.

Chen Ming, deputy manager-in-general of the Beijing Heating and Power Group, said that a clean-fuelled central heating system will help curb the capital city's pollution problems.

The group, which provides half of the city's heating, owns four heating factories - all of which use clean fuels. The rest of the city is heated with smaller, sometimes individual, heating systems.

"These can be dated back to the earlier days, when building designs did not consider central heating or pollution. It leaves problems for us now to build pipelines to send central heating inside," said Zhang Dongxue who works with the group.

Another problem is the hutong. Chen Ming said that building pipelines in hutongs would spoil the appearance of these historical and cultural symbols.

Chen suggested that using electricity is a better solution for residents living in single-storey houses there.

"Various kinds of clean energy will play important roles in heating systems in the future," Chen predicted.

He added that the central heating system will also develop towards providing air conditioning in the summer and helping produce electricity in the spring and autumn.

(China Daily November 19, 2001)