Gobi Desert from , and those of the ranges from higher, though in a few cases they reach altitudes of . The elevations do not form continuous chains, but make up a congeries of short ridges and groups rising from a common base and intersected by a labyrinth of ravines, gullies, glens and basins. But the tablelands, built up of the horizontal red deposits of the Han-gai (Obruchev's Gobi formation) which are characteristic of the southern parts of eastern Mongolia, are absent here or occur only in one locality, near the Shara-muren river. They are greatly intersected by gullies or dry watercourses.
Environmental issues in China the country. Approximately 30% of China's surface area is desert. China's rapid industrialization could cause this area to drastically increase. The Gobi Desert in the north currently expands by about per year. The vast plains in northern China used to be regularly flooded by the Yellow River. However, overgrazing and the expansion of agricultural land could cause this area to increase. In 2009, it was estimated that over 200 high-altitude lakes in Zoigê Marsh, which provides 30% of the Yellow River's water, had dried up. In 2001, China initiated a "Green Wall of China" project. It is a project to