Chad Basin depth of . Due to heavy pumping, since the start of the 1980s the water levels in both aquifers has been lowered, and some wells no longer function. There is a third, much lower, aquifer in Bima Sandstones that lies at a depth of . Both the current and historical areas of the basin and the mega-basin contain concentrations of fossils. Fossil-fuels deposits in the area are estimated to exceed a trillion barrels in reserves. The Lake Chad Basin Commission was set up in 1964 by Cameroon, Chad, Niger and Nigeria, the four countries that contain parts of Lake Chad.
Chad–Nigeria relations the 1980s. Most religious violence was domestic in origin, but Nigerian police arrested a few Libyans, and Nigerian apprehension of Libyan infiltration through Chad intensified. Nigeria's 1983 economic austerity campaign also produced strains with neighboring states, including Chad. Nigeria expelled several hundred thousand foreign workers, mostly from its oil industry, which faced drastic cuts as a result of declining world oil prices. At least 30,000 of those expelled were Chadians. Despite these strains, however, Nigerians had assisted in the halting process of achieving stability in Chad, and both nations reaffirmed their intention to maintain close ties. In May 2014, in