Geography of Uzbekistan Kazakhstan, also yielded about 60% of the total volume of Central Asia's emissions of harmful substances into the atmosphere. Because automobiles are relatively scarce, automotive exhaust is a problem only in Tashkent and Farghona. The reduction of water in Uzbekistan has resulted in soil degradation, and the spread of the salt from the evaporated Aral Sea has contaminated the surrounding soil. The soil has lost much of its water due to the increased surface irrigation. The irrigation of farmlands with water from the Aral Sea has resulted in increased salinization of the soil, causing the farmland to be less productive
Rivers of New Zealand scenic rivers. Over half of the electricity generated in New Zealand is hydroelectric power. Hydroelectric power stations have been constructed on many rivers which dam the river completely, or channel a portion of the water through the power station. There is large hydroelectric power scheme in the North Island and in the South Island where water is diverted between rivers using a system of canals that is used to maximise the electricity generation. River conservation is threatened by pollution inflows from point and non-point sources. In the past rivers had been used for pollution discharges from factories and municipal sewerage