During the Soviet period, two main rivers feeding the Aral Sea, Amu Darya and the Syr Darya, became contaminated with the pesticides and other chemicals that were being sprayed on cotton and rice fields they irrigated. These chemicals settled on the Aral seabed, and now that much of the sea has evaporated, windstorms carry the chemicals to the cities and villages hundreds of kilometers beyond. Dust storms pollute the air people breathe and the water they drink. Very high incidence of anemia, especially among children, was reported in 1997. Cancers increased. Stomach and intestinal diseases became very common.