NAIROBI -- The Chinese government has made significant steps in "greening" the 2008 Beijing Olympic Games, the UN Environment Program (UNEP) said in a study published on Thursday.

The UN environmental agency said the hosting of the games is also proving to be a catalyst for accelerating environmental improvements across the city as Beijing strives to balance rapid, often double-digit economic growth with health and environmental protection.

The report says environmental measures are being introduced covering waste management, cleaner transport systems and water treatment, as well as new urban green belts including a 580-hectare Olympic Forest Park.

"The initial score card on the Beijing Olympics and Paralympics 2008 is positive in terms of the greening of the games," UNEP Executive Director Achim Steiner said.

"The more than US$12 billion spent by the Municipal Government and Government of China appears to have been well spent and will be even more well spent if the lessons learnt and measures adopted are picked up by municipalities across the country so as to leave a real and lasting nationwide legacy," said Steiner.

He commended the Beijing Organizing Committee for the Olympic Games (BOCOG) for accelerating the phase-out of ozone depleting chemicals and for the provision of energy efficiency and green energy appliances at buildings and sports venues.

"An interesting innovation is the widespread use in the venues of ground, water or air source heat pumps systems to provide buildings with heat in winter and air conditioning in summertime," the report says.

It notes that solar power is also being extensively deployed at stadia and at the Olympic village and the organizers have well-developed plans to re-use and recycle venues after the games close.

But while the report acknowledges the significant investment and achievements of the organizers of the 2008 Olympic Games, it also highlights some remaining concerns and missed opportunities that there may still be time to rectify.

Some of these are specific to the games themselves, while others are linked to challenges facing the city of Beijing generally as it attempts to reduce pollution and steer its development onto a more sustainable path.

The report says the Beijing and Chinese authorities have relocated and refitted major polluting industries and there has been a switch away from coal-fired energy generation towards less polluting fuels like natural gas.