LHASA, Dec. 8 (Xinhua) -- A film depicting the developmental journey of Tsonyi, China's highest-altitude county in Xizang Autonomous Region, is scheduled for nationwide release on Dec. 16.

Produced to mark the 60th founding anniversary of the autonomous region this year, the film named "Puruo Gangri" is jointly presented by the publicity departments of Xizang, Zhejiang Province and Nagqu City, of which Tsonyi County is under the jurisdiction. The title refers to the Purog Kangri Glacier in the county, the thickest glacier on the Qinghai-Tibet Plateau.

With an average altitude surpassing 5,000 meters, Tsonyi County covers nearly 120,000 square km within the Changtang National Nature Reserve. The area has only about 40 percent of the oxygen found at sea level. Winters can last up to 10 months, with temperatures plunging as low as minus 40 degrees Celsius.

Through the story of young university student Tong Xiaofan and local herders, the film chronicles the county's transformation from its establishment to a recent ecological relocation program -- a move to improve people's living conditions and protect the fragile local ecosystem.

The crew filmed for 62 days at altitudes above 5,000 meters, with the highest shooting point reaching 5,800 meters.

"We overcame immense difficulties. This shoot was an ultimate challenge," said Cai Yu, co-director of the film, adding that many team members suffered from altitude sickness during production.

A remarkable scene features actor Ngawang Rinqen leaping into an icy river to rescue a drowning yak. With temperatures plummeting to minus 27 degrees Celsius at an altitude of 5,300 meters above sea level, hair would freeze within seconds of emerging from the water.

"For that scene, I spent over 40 minutes submerged in the icy river in total," said the Tibetan actor. "As a professional actor, I wanted to portray the real state of the prototype characters."

The film is based on the experiences of local officials and herders. One of the prototype figures, grassroots official Sangda Tsomo, expressed gratitude to the production team for bringing Tsonyi's story to the big screen.

"Tsonyi County has been my home for 15 years. Those glimmers of hope from the 'no-man's land' deserve to be remembered," she said. ■