Environmental responsibilities are vested in the Under Secretariat for Environment and in the Ministry of Energy and Natural Resources. Among Turkey's principal environmental problems is air pollution in Ankara and other cities. The smog in Ankara grew worse after 1979, when the government banned oil heating systems in new buildings in order to reduce costly oil imports; the resultant increased burning of Turkish lignite, which is high in sulfur content, greatly increased the levels of sulfur dioxide and dust in the air. In 1983, the government reversed itself and banned the conversion of heating systems to coal. At the same time, it introduced an antipollution program designed to reduce air pollution levels by more than 50% within a year. In addition to heating restrictions, the plan called for strict traffic controls, the closing of the worst industrial polluters, a prohibition on the import of high-sulfur fuel oil, special emergency hospital wards for smog victims, and the building of green areas and parks in and around cities. In 1992, Turkey had the world's highest level of industrial carbon dioxide emission, which totaled 145.5 million metric tons, a per capita level of 2.49 metric tons. In 1996, the total rose to 178.3 million metric tons.
A $220-million project to clean up the polluted water in the Golden Horn, an inlet of the Bosporus forming a harbor in Istanbul, was implemented in the 1980s. The nation's rivers are polluted with industrial chemicals. Among them, mercury has created a serious threat to the nation's water supply. As of 2000, only 81% of urban dwellers and 86% of rural residents have access to safe drinking water. Soil erosion affects both coastal and internal areas. The combination of water and wind eliminates 500 metric tons of soil each year.
In 2001, 15 of Turkey's mammal species and 14 of its bird species were endangered. About 1,600 types of plants were threatened with extinction. Endangered species include the Anatolian leopard, Mediterranean monk seal, bald ibis, slender-billed curlew, Atlantic sturgeon, and hawksbill and green sea turtles.