The Secretariat for Urban Development and Ecology (SEDUE) has the principal environmental responsibility. One of Mexico's most widespread environmental problems is soil erosion; slash-and-burn agricultural practices, especially in the tropical zones, have also contributed to deforestation. Mexico loses its forest at a rate of about 0.9% annually due to agricultural and industrial expansion. Mexico has the fourth most extensive mangrove area in the world, covering approximately one million hectares. Mexico City, located more than 2,250 m (7,400 ft) above sea level and surrounded by mountains, has chronic smog, aggravated by the presence in the metropolitan region of thousands of factories, more than two million motor vehicles, and by open burning of garbage by slum dwellers in an attempt to dispose of the 30% of the city's refuse that is not regularly collected. Cities along the US-Mexican border also suffer from serious air pollution. In 1996, Mexico's level of industrial carbon dioxide emissions totalled 348.1 million metric tons. Transportation vehicles are responsible for 76% of the air pollution. Water pollution results from the combined impact of industrial, agricultural, and public waste. Mexico's cities produce over 12.9 million tons of solid waste per year along with about 164 million tons of industrial waste. Mexico has 409 cu km of renewable water resources. In the north, fresh water resources are scarce and polluted; in the central southeast region they are frequently inaccessible and of poor quality. Only 69% of the nation's rural dwellers have pure drinking water. An environmental protection statute adopted in 1971 has not been widely enforced; however, SEDUE, which was created in 1982, is fostering a more coherent approach to environmental issues.
In 2001, 64 of the nation's mammal species and 36 bird species were endangered. Endangered species in Mexico include the volcano rabbit, Mexican grizzly bear (possibly extinct), Lower California pronghorn, Sonoran pronghorn, imperial woodpecker, southern bald eagle, American peregrine falcon, tundra peregrine falcon, horned guan, masked bobwhite quail, whooping crane, light-footed clapper rail, California least tern, maroon-fronted parrot, ridge-nosed rattlesnake, Bolson tortoise, five species of turtle (green sea, hawksbill, Kemp's ridley, olive ridley, and leatherback), bighead pupfish, blackfin skiffia, San Estebán Island chuckwalla, spectacled caiman, two species of crocodile (American and Morelet's), and totoaba. At least 30 species have become extinct, including the Mexican dace, Durango shiner, Tlaloc's leopard frog, and the Caribbean monk seal.