While questions of slum redevelopment and mass transit dog Indian cities in their quests for modernity, a far more basic concern will make or break said aspirations … water. Unless solutions are found to India’s rapidly depleting water table, Delhi runs the risk of going the way of Fatehpur Sikri and Babel.
Northern India, according to most estimates, will run out of water in the next 15 years. Like Mexico City, massive urbanization, illegal water tapping, waste and poor government enforcement have exacerbated the problem. Unlike Mexico City, Northern India experiences a routine wet season that, if managed properly could mitigate the alarming depletion of its underlying water table. However, according to a NASA study, the states of Punjab, Haryana & Delhi and Rajasthan have not developed the catchment programs necessary to reduce over-harvesting and are still withdrawing much more than their groundwater recharge rates . In fact India as a whole runs a yearly 17 cubic mile deficit (18.5 trillion gallons).
Surprisingly, peak water has never been quite as fashionable as peak oil (until Bond’s Quantum of Solace) in spite of its far more fundamental role in human, animal and vegetative survival . Without delving too deep into the theory, there are three types of potable water: underground aquifers that have built up over millennia (non-renewable stock water), surface rivers and lakes (stock of renewable water) and rainfall (flow of renewable water). As global populations have grown and exploited surface water, they have increasingly drilled deep into the underground aquifers, emptying them faster than rainwater can refill them. While this is not troubling globally, as the earth has enough water, distributing this plenty to the stressed regional water systems involves prohibitively high cost and difficulty (think of Mexico City’s problems on a much larger scale). The only equitable and feasible option is better water management.
In India the main causes of Indian water table depletion are:
1)Agriculture 2)Increased urban density
While I am a neophyte in this field, travel in Israel and Singapore (two water-starved nations) shed light on some interesting water management techniques to ameliorate India’s deteriorating water situation :
– Reclaimed wastewater for agricultural use (52% of agricultural water in Israel is reclaimed)
– Drip hose irrigation for agriculture (Israeli & Indian companies lead this sector)
– Rainwater collection on all housing developments for artificial aquifer recharge (separate drainage systems avoid issues of cross-pollution with wastewater)
– Advanced membrane technology water purification to create potable water
– Setting realistic water tariffs (agricultural water is currently free!), reducing leakage and pilfering through capital improvement plans (new pipelines)
– Better trash & sanitation management to avoid pollution of existing surface freshwater
 a more academic definition of the term: http://www.pnas.org/content/107/25/11155