The water crisis silently developing beneath Mexico City is getting harder to ignore.
With the underground aquifer that provides most of the Mexican capital's fresh water drying at an alarming rate, the city is ever more reliant on topping up supply from the dams, pipes, and pumps of the Cutzamala system, more than 60 miles away.
Maintenance work on that system has now temporarily cut off supply for about a quarter of the city's 22 million inhabitants.
"These are very important emergency measures for the city," Ramón Aguirre, head of water management in the city, told reporters. "Everybody should be careful with water. They should wash using a bucket and a bowl."
The cut off started at the stroke of midnight last Wednesday and is due to last until Tuesday morning. The authorities say a full normal service will not be reestablished until next Friday.
Such interruptions in Mexico City's water supply have become a periodic feature of life in the metropolis over the last five years, but this time it is lasting longer than usual.
The federal government has promised there will be fewer breaks once it has finished constructing new pipes in Cutzamala system, which was built in the 1970s. But this does not address the deeper problem that there is no let up in the draining of the aquifer.
Every year the city extracts 1.3 billion cubic meters of water while rainfall, and some injection, only recharges it by 700 million cubic meters. In other words, it is losing water at nearly double the rate at which it is being recharged.
Virginia Cervantes, from the Social Sciences Institute of the National University of Mexico, says the problem of finding fresh water is compounded by social inequality that ensures that the biggest consumers almost never run out, while the smallest often do.
"Inequality and the gap between the rich and the poor also have a say in the matter," she wrote in a report last year. "The average daily consumption is only 28 liters per person in the poorest areas of the city. In the wealthiest areas it is between 800 and 1,000 liters."
While the rich have large tanks on their roofs that mean their basic water needs can always be met, even if the supply is cut off for days, many residents of poor barrios constantly struggle with taps running dry.
Large quantifies of people living with an insufficient and unpredictable water supply represents a constant source of social tension in some parts of the Mexican capital.
With the current cut off of supply affecting millions, police were put on alert throughout the city. A source in the police department, however, told VICE News that there has been just one "minor incident" so far. He said angry citizens and police officers clashed in the low income borough of Iztapalapa, where patchy water supply has long been a major problem.
Perhaps the most serious conflict took place in 2014 when dozens were injured during clashes between police and protesters broke on in the barrio of San Bartolo Ameyalco on the mountainous outskirts of the city. Protesters claimed they were defending a fresh volcanic spring from plans to move the water to a nearby wealthy community.
Brenda Rodríguez, from the Mexican NGO Coalition of Mexican Organizations for the Right to Water, also points to the issue of the quality of the water. This too is particularly bad in poorer areas.
"In Mexico there are 13 million people who, like in Iztapalapa, have access to running water but it is contaminated by either fecal matter and heavy metals." she told reporters last year.
Related: The World Is Running Out of Water
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