DOUALA, CAMEROON - Dawn breaks in Cameroon's economic hub, the seething metropolis of Douala, and a crowd gathers at the water spigots by the Guinness brewery in the run-down district of Bassa. The hole is one of a huge number of privately-owned wells which dip into the water table in this region of four million people. But lack of regulation has led to chaos, raising questions as to whether the precious resource can be sustained or remain drinkable.