Mexico City is running out of water—are these cities next?

Drought, urban development, and poor management are causing an unprecedented strain on urban water supplies across the world.

Record-breaking heat and years of mounting drought, capped last June by El Niño winds that cut the rainy season short, have pushed Mexico City’s water reservoirs into a historic deficit. As of this month, reservoirs sit at less than 27 percent capacity. 

The consequences in Mexico City have so far been devastating: more than 550 neighborhoods have had their tap water turned off or their water pressure reduced, according to one analysis of data from a local water authority. These water saving measures are forcing residents to fill whatever jugs they can gather at irregular and costly tanker deliveries. As summer begins, the megacity of 23 million is on the brink of disaster.

If heavy rains don’t arrive soon, in late June the city’s Cutzamala water system could reach “Day Zero,” a doomsday estimation that marks the moment the reservoirs will stop pumping. That means that in as much as a quarter of the city—even zones that have typically escaped water shortages—the taps would go bone dry. The aquifers where about 70 percent of the city’s water comes from will keep flowing, but they too are in danger.

“We’re in a truly awful situation,” said José Luis Luege, a former head of the national water commission and adviser to the country’s political opposition who helped popularize Mexico City’s Day Zero deadline. “At this point, I’m really betting on a miracle.”

Across the world, climate change is exacerbating droughts, sending urban areas already set back by unchecked development and aging water infrastructure into unprecedented territory. The idea of Day Zero, used globally to help turbo-drive water-saving campaigns, has proved a helpful threat.

Here’s how some of the most water-starved cities are grappling with their own Day Zero fears. 

Bogotá, Colombia

Rolling water cuts have roiled the Colombian capital of Bogotá since April, after the Chingaza reservoir system that provides more than two-thirds of the city’s drinking water dropped to a staggering 17 percent capacity. Running water in neighborhoods across the city of eight million is shut off three times a month and households are subject to hundreds of dollars in fines if they go over monthly allotments. 

“The entire city must be in water saving mode,” Mayor Carlos Fernando Galán warned as he announced the restrictions, along with PSAs that reflected the desperation: shower with your partner—or not at all, if you don’t plan to leave your home.

While experts have criticized the city for waiting too long to implement rationing, under the policy, the water level in the Chingaza system ticked back up, topping 36 percent capacity earlier this month. Still, the measures could remain in place through October as the reservoirs fill to a target amount.

Delhi, India

In 2019, the coastal city of Chennai, India, struck a form of Day Zero when its four main reservoirs completely dried out, leaving its 10 million residents dependent on a shrinking groundwater supply and trucked-in water. 

“You had to spend a lot of time to get [water], you had to spend a lot of resources to get it,” said Raj Bhagat Palanichamy, a senior program manager in the sustainable cities and transport program of World Resources Institute, India.

Today, water scarcity in India is being felt most sharply in Delhi, where a recent video of residents swarming a water tanker was filmed and shared widely online. With several days of summer still left before the monsoon season brings rain, levels of the river they draw water from are unusually low. A water sharing agreement between the states that border the river that experts call insufficient has led to disputes.  

Barcelona, Spain

The tourist-mecca of Barcelona devolved into backbiting this year as dwindling water supplies pitted visitors against locals. In March, following three years of drought, levels in the Ter-Llobregat water system hit an all-time low, below 15 percent, triggering emergency water restrictions.