A senior United Nations Environmental official has rebuffed criticism of the air quality at the Olympic Games in Beijing saying efforts to reduce pollution have been impressive. The official also announced that Chinese basketball star Yao Ming has become a goodwill ambassador for the organization. VOA's Scott Bobb reports from the Chinese capital.

Motorists drive past Beijing Olympic national stadium, known as Bird's Nest covered with hazy skyline, 28 Jul 2008

The head of the U.N. Environmental Program, Achim Steiner, Saturday said air pollution remained a concern during the Olympic Games and would be monitored continuously. But he said Chinese efforts to address the problem have shown notable results. "Beijing has invested more effort and more resources (into the environment) than any other (Olympic) host city before and I think the diversity of measures here that have been taken have been very impressive," he said.

Steiner said the measures include the installation of 150 kilometers of public transportation networks, construction of a large park in the heart of the city and a significant reduction in the level of particles in the air.

Authorities closed factories and halted construction around the city and restricted private vehicles on alternate days depending on their registration numbers.

Nevertheless, the sky over Beijing has been shrouded in haze, due in part to high humidity and a lack of rain, leading to fears for the health of the ten thousand athletes competing in the Games.

The U.N. official Steiner recalled that pollution levels were a major concern at previous Olympic Games in Los Angeles (United States) and Athens (Greece). He said in Beijing they have remained below the danger zones so far but that if they deteriorated Olympics officials were prepared to postpone or relocate events.

Steiner said the concerns in Beijing are mainly for the long-term. "In the areas of particle matter, water resources management, water quality, there is significant room for further development. And finally the question is will Beijing continue to invest in its public transport infrastructure? And I think that will be a big test for the long-term impact of the Games," he said.

Steiner also announced that Chinese basketball star Yao Ming had been named the United Nations' first Environmental Champion and would seek to promote awareness of environmental issues and climate change around the world.

Ming issued a statement saying athletes could play a major role in this effort and called on organizers of major sports events to encourage the use of public transportation, proper waste management and greener forms of energy.