"Sixteen billion dollars is not a small commitment by any means. Who can say that's small?" he said.

The official described the cooperation between the UNEP and the Beijing Organizing Committee for the 2008 Olympic Games (BOCOG) as positive and productive.

"We made suggestions and they've been indeed listened to," he said.

After seven years of preparation, Beijing is confident of honoring its Green Olympic commitment with the support of Chinese people and the international community, said Liu Qi, head of the BOCOG, earlier this week, adding the city had put an emphasis on controlling air pollution and promoting landscape greening.

"I'd like to call on all parties to be supportive while people are doing or try to do something for the environment," said Bindra. "Change has to be incremental. It's not going to come suddenly."

"Large sporting events have large footprints. But more importantly, sporting events send messages to hundreds of millions of people. If you look at the audience of this Olympics, we are talking about four billion people who are going to watch. It sends a message not just to China, but also to others," he said.

"People now are really concerned (about sports)and sports has to be a very main provider as far as thinking, caring, nourishing, nurturing environmental concerns."