History of Chad Africa's major language groupings south of the Sahara Desert (except Khoisan, which is not considered a valid genetic grouping anyway), i. e. the Afro-Asiatic, Nilo-Saharan and Niger–Congo phyla, originated in prehistoric times in a narrow band between Lake Chad and the Nile Valley. The origins of Chad's peoples, however, remain unclear. Several of the proven archaeological sites have been only partially studied, and other sites of great potential have yet to be mapped. At the end of the 1st millennium AD, the formation of states began across central Chad in the sahelian zone between the desert and the savanna. For
Niger Basin Authority from the threats of desertification, deforestation and pollution of the rivers by agriculture and industry have become a major theme of their work. Nine nations which include part of the Niger Basin are members: Benin, Burkina Faso, Cameroon, Chad, Côte d'Ivoire, Guinea, Mali, Niger and Nigeria. While a small area of Algeria falls within the Niger Basin, it is not a member of the NBA. It is based in Niamey and works in both French and English. Ministers representing the Authority's members meet in yearly session at the headquarters in Niamey, as well as locations in the member states. Additionally,