People in the region are calling for moves to tackle the growing issue of 'white pollution'. 

During a waste collection session in May at the base of Qomolangma, known in the West as Mount Everest, in the Tibet autonomous region, participants put garbage into bags and prepare to transport it downhill. JIGME DORJE/XINHUA

Dressed in camouflage and a blue vest, Samdrub squeezed a ragged, dusty blouse into a woven sack bulging with broken beer bottles, crushed biscuit tins, plastics and other garbage.

She dragged the sack to a blue truck parked a few hundred meters away. The truck stood near a single-lane road that led to a Buddhist temple sitting atop a mountain in a northern suburb of Lhasa, capital of the Tibet autonomous region.

Scores of similar sacks were piled up along the roadside, waiting to be loaded onto the vehicle. Not far away, a couple of sheep roamed the deserted land looking for grass.

"Loads of garbage here. Loads of it. This is the fifth consecutive time we have come here and we still haven't finished the cleanup," said Samdrub, 64, who like many Tibetans only uses one name.

The retired electrician was collecting trash on a patch of deserted land alongside scores of other volunteers on the hillside, which overlooks the Lhasa River, the northern tributary of the Yarlung Tsangpo River, in the south of the city.

Samdrub and her companions are members of a regular cleanup campaign organized by the Lhasa Ban-White Association, an environmental advocacy group established in October.

The association taps the volunteer spirit on the plateau to control abandoned plastic trash, aka "white pollution".

The volunteers are of all ages and come from different walks of life, but many of the most active are members of the Tibetan ethnic group who were born in the region's preindustrial era, when plastic was rarely used.

Now retired and with time to kill, Samdrub and her friends have taken to the city's ravines and riverbanks to battle pollution that is fueled in large part by urbanization and growing consumerism in the region.

"In recent years, I've read reports that livestock choked and died after eating plastic. I was born and raised in rural Shigatse (Tibet's second-largest city), and I know how big a financial loss that is for herders," Samdrub said.

Wangdu, a retired violinist with the Shigatse Art Troupe and a member of the cleanup crew, said he learned about the activity a few months ago via photos friends had shared on WeChat.

"I run a musical instrument shop in downtown Lhasa and I occasionally give myself a break by joining such activities. My children are very supportive," the 66-year-old said.