Ranbir Singh still remembers when the wells in his village on New Delhi's southwestern edge were filled with sweet-tasting water and livestock drank from the small ponds that dotted the area.
Now the village has been all but subsumed by Dwarka, a high-rise satellite city that sprang up in the 1990s on the edge of India's sprawling capital.
The ponds dried out long ago and are now filled with rubbish, while over-extraction has caused the groundwater level to fall so far that industrial pumps are needed to bring water to the surface.
"Today what you get from underground is not even drinkable," the 62-year-old told AFP in Pochanpur, now a hodgepodge of small-scale construction overshadowed by Dwarka's tower blocks.
"People who still consume it complain of stomach problems, and many young people in our village suffer from skin problems because of this water."
Decades of population growth and uncontrolled urbanisation have created a water crisis in India.
The World Resources Institute, a Washington-based research group, says the national supply is predicted to fall to 50 percent below demand by 2030.
A new UN report to be launched in Delhi on Friday ahead of World Water Day on March 22 will warn of an urgent need to manage the world's water more sustainably and highlight the problem of groundwater over-extraction, particularly in India and China.
It says 20 percent of global groundwater sources are already over-exploited and warns the problem will only become more acute without better management, with demand expected to rise by 55 percent by 2050.
- Contaminated rivers -
Sushmita Sengupta of the Delhi-based Center for Science and Environment says much more could be done to manage supplies in India.
"Our lakes and ponds were once a natural way of recharging groundwater, but they are being destroyed through urbanisation," she said.
"Our sewage goes untreated, so the rivers are contaminated. We used to be very good at managing water in India, but we are losing that ability."
Activist Diwan Singh is campaigning for the city to divert rainwater drains, which currently flow into the sewage system, to lakes and ponds in order to replenish the water table.
The 44-year-old experienced Delhi's water woes first hand when he moved into a tower block in Dwarka, which like many parts of the capital receives no piped water and has to rely on tanker deliveries and borewells.
"Delhi's groundwater management has been dismal," complained Singh, who says he faces an uphill struggle against a slow-moving and sometimes corrupt bureaucracy.
"In some areas around Dwarka, the groundwater level has fallen by 200 feet (60 metres). Meanwhile all the water that falls in the monsoon is being drained into the sewers and lost."
The result is that in many parts of Delhi the groundwater contains such a high concentration of impurities that it is undrinkable.
- 'People get very angry' -
A few kilometres away from Dwarka's modern high-rises in the working-class suburb of Kailash Puri, life revolves around the city water board's twice-weekly deliveries.
Residents used to drink water drawn from the ground with borewells, but that is now too toxic, and few can afford the expensive water purifiers that are a standard feature of Delhi's wealthier households.
As the water board's brightly-coloured trucks roll down the street, entire families including small children dash out of their homes with plastic containers to fill.
"I was supposed to be at a job interview today, but I had to miss it because the water was coming," said 22-year-old Neha Rana as she filled her buckets.
"It doesn't matter what's going on, you have to come and get the water. At times people get very angry, and fights can break out."
No one at the Delhi water board would speak to AFP on the record, but an official speaking on condition of anonymity said this was a national crisis and could not be resolved at the state level.
"It is an issue that needs concerted, long-term planning at the national level," he said.
The issue has become so big in Delhi that providing free water was one of new Chief Minister Arvind Kejriwal's key campaign promises in state elections last month.
In the meantime, private water "mafias" are catering for demand unmet by the government -- at a price.
Many source their water from illegal borewells, exacerbating the problem, and there have been reports they collude with water board officials to create an artificial shortage.
"They can recharge their pockets but they can't recharge the groundwater," said Singh, the Dwarka campaigner, as he looked despondently at the empty pond in the park near his home.