Fergana Valley and elsewhere. During the Soviet Era, a plan was devised in which Kyrgyzstan and Tajikistan provided water from these two rivers to Kazakhstan, Turkmenistan, and Uzbekistan in summer, and these three countries provided Kyrgyzstan and Tajikistan with oil and gas during the winter in return. However, this system dissolved after the collapse of the USSR, and a new resource-sharing plan has yet to be put in place. According to the International Crisis Group, this situation could lead to irreparable regional destabilization if it is not resolved. A shallow lake, Sarygamysh Lake, sits on the border with Turkmenistan. Another important feature of Uzbekistan's physical environment is the significant seismic activity that dominates much of the country. Indeed, much of Uzbekistan's capital city, Tashkent, was destroyed in a major earthquake in 1966, and other earthquakes have caused significant damage before and since the Tashkent disaster. The mountain areas are especially prone to earthquakes. Climate Uzbekistan's climate has sometimes been broadly described as Mediterranean and humid continental, meaning that it has both relatively hot summers and relatively cool winters. However, only a small area in eastern Uzbekistan is classified as Mediterranean and humid continental under the Köppen climate classification. A vast majority of its total area – including all of the sparsely-populated western and central regions – is classified as either cold desert (Köppen BWk) or cold steppe (BSk). Summer temperatures often surpass ; winter temperatures average between and , but may fall as low as . Most of the country also is quite arid, with average annual rainfall amounting to between and occurring mostly in winter and spring. Between June and September, little precipitation falls, essentially stopping the growth of vegetation during that period of time. Environmental problems Despite Uzbekistan's rich and varied natural environment, decades of environmental neglect in the Soviet Union have combined with skewed economic policies in the Soviet south to make Uzbekistan one of the gravest of the CIS's many environmental crises. The heavy use of agrochemicals, diversion of huge amounts of irrigation water from the two rivers that feed the region, and the chronic lack of water treatment plants are among the factors that have caused health and environmental problems on an enormous scale. Environmental devastation in Uzbekistan is best exemplified by the catastrophe of the Aral Sea. Because of diversion of the Amu Darya and Syr Darya for cotton cultivation and other purposes, what