The hunger crisis in the Sahel region of Senegal, Mauritania, Mali, Burkina Faso, Niger and Chad has been deepening since the start of this year.

The Sahel is a classic transition zone–a border that is not a sharp division, but a gradual shift from one region to the next.  This area has environmentally marginal lands, but is as population pressures continue, marginal lands need to sustain more people. 

See on www.guardian.co.uk