An estimated 4 billion people live in areas that suffer from severe physical water scarcity for at least one month per year.

Water stress, essentially measured as water use as a function of available supply, affects many parts of the world. Over two billion people live in countries experiencing water stress. Physical water stress is often a seasonal rather than an annual phenomenon, as exemplified by the seasonal variability in water availability. An estimated four billion people live in areas that suffer from severe physical water scarcity for at least one month per year. About 1.6 billion people face ‘economic’ water scarcity, which means that while water may be physically available, they lack the necessary infrastructure to access that water (Comprehensive Assessment of Water Management in Agriculture).

 Several of the world’s main aquifers are under increasing stress and 30% of the largestgroundwater systems are being depleted. Water withdrawals for irrigation are The primary driver of groundwater depletion worldwide.