Chinese Vice Premier Liu Yandong reads a congratulatory letter sent by Chinese President Xi Jinping to a research team on an expedition to the Qinghai-Tibet Plateau, in Lhasa, capital of Southwest China's Tibet autonomous region, Aug 19, 2017. [Photo/Xinhua]

Xi expressed his congratulations and greetings to scientists, young students and support staff who joined the country's second comprehensive scientific expedition to the plateau.

Xi said that they should focus on problems related to carrying capacity of the resources and the environment, disaster risk as well as green development on the plateau, according to the letter.

The Qinghai-Tibet Plateau is an important ecological safety barrier and strategic resource reserve base, Xi said in the letter.

He noted that the expedition will promote the plateau's sustainable development and the world's ecological environmental protection.

Vice Premier Liu Yandong read the letter at a ceremony in Lhasa, capital of southwest China's Tibet Autonomous Region.

The expedition, led by the Chinese Academy of Sciences, will analyze the impact of environmental change on social development and provide suggestion for the building of a national park in the area.

China's first comprehensive scientific expedition to the plateau began in the 1970s.

A large number of materials accumulated have provided solid scientific basis for economic and social development as well as environmental protection in the region.