The last 20-30 years have witnessed a ’global boom’
in groundwater use for irrigation in areas subject to
extended dry seasons and/or regular droughts
(Llamas, 2005). In India, for example, the
groundwater-irrigated area has increased 500%
since 1960 (Shah, 2009). Satisfactory global
statistics for groundwater irrigation are now
available from a UN-FAO survey