Mexican citizens overwhelmingly voted to cancel a half-built airport outside of Mexico City, the Associated Press reports. The $13 billion project, which is already a third of the way built, was plagued by accusations of corruption and the threat of ecological damage.

President-elect Andres Manuel Lopez Obrador proposed the referendum after winning the election but before taking office, Architects Newspaper reported. On Sunday, one million voters (just about one in 90 registered voters in Mexico) came out, voting to reject the airport 70 to 29 percent.

As Next City reported in May, ecologists contended that building the airport in its proposed location would both exacerbate Mexico City’s drinking water scarcity while making it more vulnerable to floods. This paradox comes from the fact that all of Mexico City is built on an ancient lakebed, known as the Texcoco basin, without much natural drainage.

“As a consequence, the Mexico City of 2018 is both severely dehydrated and struggling with devastating floods,” Paulo Cisneros reported for Next City. “The city’s massive concrete footprint prevents rainwater from refilling the aquifers beneath its residents’ feet. That, in turn, causes the city to sink deeper into the marshy lakebed, lessening the effectiveness of its gravity-dependent drainage systems. The end result is a metropolitan region of more than 20 million residents in which drinking water is sparse while wastewater collects in the streets.” The new airport would have exacerbated both these problems, according to a nonpartisan scientific group’s analysis. It would have reduced the region’s natural drainage, adding to floods, and consumed 23 million cubic meters of water a year, CityLab reported.

“It’s just the worst terrain,” Fernando Córdova, environmental impact specialist and a professor at the National Autonomous University of Mexico, told Alto Nivel (later translated in CityLab). “There’s a reason why this part of the city hasn’t ever been urbanized.”

Critics also worried about the environmental impact on the 130 bird species found in Texcoco and the urban sprawl that the airport could exacerbate.

Lopez Obrador had railed against the airport since before getting elected, Reuters reported; in March, he called the airport project and its corporate backers “corrupt” but declined to elaborate on how the corruption took place. He also dismissed concerns that canceling the airport would cause uncertainty, the wire service said.

“Yes, that’s what they say: uncertainty. But then what? To prevent uncertainty I’m going to become an accomplice to corruption? No. I’d prefer there to be uncertainty,” he told Reuters.

The airport, designed by Foster+Partners, has already been partially built — and $5 billion already spent. It would have been the third largest airport in the world and handled 125 million people a year.

Now that the project is dead (Lopez Obrador says he will honor the will of the people — “The decision taken by the citizens is democratic, rational and efficient,” he told the AP) Mexico City still needs a new airport. The current airport is at capacity with 40 million passengers a year, Reuters said. Lopez Obrador favors converting a military air base to civilian use, adding two runways, and then connecting the existing airport with the new one by road. He said the project can be done for $3.5 bililon.

Lopez Obrador said that he hoped the unfinished airport could become “a big sports and ecological complex” for the city, according to the AP.

Rachel Kaufman is Next City's senior editor, responsible for our daily journalism. She was a longtime Next City freelance writer and editor before coming on staff full-time. She has covered transportation, sustainability, science and tech. Her writing has appeared in Inc., National Geographic News, Scientific American and other outlets.

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