A shortage of potable water inhibits agriculture, animal husbandry, and human settlement in much of Sudan. Sudan has 35 cu km of renewable water resources, of which 94% is used for farming and 1% is used for domestic purposes. Serious health problems are caused by diseases carried in the water supply; Only about 69% of the nation's rural dwellers and 86% of its city dwellers have pure drinking water. The water on the nation's coasts is also polluted by industrial by-products, oil, and sewage. Sudan's cities produce about 1.1 million tons of solid waste per year. The nation's agricultural land is threatened by the advance of the desert. Government agencies vested with environmental responsibilities include the National Committee for Environment (within the National Council for Research) and the ministries of Agriculture, Natural Resources, Irrigation, Energy, and Health. Due to uncontrolled hunting, the nation's wildlife is threatened. As of 2001, 21 mammal species and 9 bird species are endangered, as well as 2 types of plants. Endangered species include the waldrapp, northern white rhinoceros, Tora hartebeest, slender-horned gazelle, and hawksbill turtle. The Sahara oryx has become extinct in the wild.