Vice-Premier Liu Yandong (C) reads a congratulatory letter at a ceremony in Lhasa, capital of Southwest China’s Tibet autonomous region. The letter was sent by President Xi Jinping on Aug 19 to a research team conducting expedition to the Qinghai-Tibet Plateau. 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. [Photo/Xinhua]