"My whole body was almost completely soaked," he said. "I was cold and tired. I had to spend more than three hours traveling the last 5 km, and I had to stop frequently to rest."

Lin said the tourism service center was about to close when he arrived, and he was lucky he did not have to spend the night outside because it snowed the whole night.

Another time, the brakes on his tricycle failed on a downhill section of the highway and he was forced to use his feet to slow down. He then had to spend hours pushing the tricycle to the nearest county town for repairs.

He usually camped at night but would stay at an inn once a week.

"I thought the lack of garbage bins was the main reason for the waste everywhere, but that is not true because I found this time that tourists litter everywhere in the tourism zones," Lin wrote on his micro blog.

To raise people's awareness of the need to protect the environment, he had a banner on his tricycle reading, "The purest land is the people's heart."

While his trip has made the road cleaner and inspired and educated many people, his mother did not support the idea at first. She told him embarking on such a trip was foolish and risky, but later she changed her mind.

"My mom said she was sorry to see her son looking older and more like a garbage recycler in pictures, but she also said what I have been doing is a thing with lifelong meaning," Lin, originally from Jiangxi province, said.

He took the trash he and others collected to the nearest garbage station for disposal or asked the drivers of passing cars to ferry it to a garbage station for him.

Lin said he saw the most garbage at Tibet's Khatse La Mountain, where he collected six bags of trash in the space of two hours.

"Another place I saw a lot of waste was near Anjiula Mountain," he said. "There was a lot of waste on the grassland, in the river and in the wetland - everywhere.

"I heard many nomads talking and laughing happily on the grassland, but I cannot be happy seeing a pastoral scene surrounded by waste."