London ? Bangladesh and Chad were ranked most corrupt on a global watchdog group’s annual list of corruption levels in 159 nations, released Tuesday. At the other end of the scale, Iceland was ranked least corrupt.

Corruption undermines efforts to eradicate poverty, with graft by public officials hampering attempts to raise the living standards of the poor, Transparency International said.

“Corruption must be vigorously addressed if aid is to make a real difference in freeing people from poverty,” said Peter Eigen, chairman of the Berlin-based group.

To form its annual corruption index, Transparency International asked businessmen, academics and public officials about how countries they live in or do business with are perceived.

On a scale of one to 10, Bangladesh and Chad both scored 1.7, meaning that graft is perceived as being rampant. The least corrupt country, Iceland, scored 9.7.