The many lakes of Asia vary considerably in size and origin. The largest of them—the Caspian and Aral seas—are the remains of larger seas. The Caspian has been fluctuating in size, and the Aral has been shrinking, primarily because its tributaries, the Amu Darya and the Syr Darya, have been tapped heavily for irrigation purposes. Lakes Baikal, Ysyk-Köl, and Hövsgöl (Khubsugul), the Dead Sea, and others lie in tectonic depressions. The basins of Lakes Van, Sevan, and Urmia are, furthermore, encircled by lava, and Lake Telets was gouged out by ancient glaciation. A number of lakes were formed as the ...(100 of 38030 words)