BEIJING - Huge amounts of garbage line the Qinghai-Tibet Highway on the namesake plateau in west China, posing severe threats to local ecology, recent research found.

As part of a garbage pollution survey initiated by the China Environmental Protection Foundation and other groups, 40 volunteers cleared nearly 160,000 pieces of litter from a 450-km section of the route touted as "The Road to Heaven" between October 12 and 18, according to a Thursday news conference held by the project organizers.

At an elevation of about 4,000 meters, that part of the route is located in the source area of the Yangtze River and is adjacent to the two state-level nature reserves of Kekexili and Sanjiangyuan.

Some 63,602 pieces, or 40 percent of the total collected, were plastic bottles, while pop cans took up 27 percent and plastic bags and wrappings accounted for 16 percent.

According to the survey, food, drink bottles and the wrappings of daily necessities contributed 97 percent of all garbage collected.

Environmental protection groups noted at the conference that the Qinghai-Tibet Plateau, as the source area for many major rivers in China as well as an essential ecological barrier in the west, will be hard to rehabilitate once its fragile ecosystem is damaged by pollution, and that such damage might lead to chain reactions.