Nigeria Sudan savannah is similar but with shorter grasses and shorter trees. Sahel savannah consists of patches of grass and sand, found in the northeast. In the Sahel region, rain is less than per year and the Sahara Desert is encroaching. In the dry northeast corner of the country lies Lake Chad, which Nigeria shares with Niger, Chad and Cameroon. Nigeria's Delta region, home of the large oil industry, experiences serious oil spills and other environmental problems, which has caused conflict. Waste management including sewage treatment, the linked processes of deforestation and soil degradation, and climate change or global warming are
Chad Basin the Wadai capital of Abéché was occupied by the French. The remainder of the basin was divided by the British in Nigeria who took Kano in 1903, and the Germans in Kameroun. The countries of the basin regained their independence between 1956 and 1962, retaining the colonial administrative boundaries. As of 2011, over 30 million people lived in the Chad Basin. The population is growing rapidly. Ethnic groups include Kanuri, Maba, Buduma, Hausa, Kanembu, Kotoko, Bagger, Haddad, Kuri, Fulani and Manga. The largest cities are Kano and Maiduguri in Nigeria, Maroua in Cameroon, N'Djamena in Chad and Diffa in Niger.