López Obrador cancelled plans for a huge brewery on Mexico’s northern border last year, and on Sunday he questioned the whole idea of producing beer for export.

“How can we have beer breweries in the north? How can we produce beer for export? What are we exporting? Water. We don’t have water in the north,” López Obrador said.

Mexico has the largest beer export sector in the world, with about $4.6 billion worth exported annually, largely to the United States.

The president’s comments came during a ceremony in northern Mexico marking efforts to restore more water flow to Cuatro Cienegas, a system of marshes and saline pools that support cyanobacteria colonies and other species not found elsewhere.

The government says it has increased water flow to the marshes, and recovered about 100 acres (40 hectares) of wetlands that had dried out.

Local milk production and the water consumption to grow cattle feed is putting the unique ecosystem at risk.

López Obrador criticized milk production around Cuatro Cienegas, which is in an otherwise arid region of Coahuila state.

“Milk is (basically) water,” López Obrador said. “Why not use the water of south and southeast” Mexico, where he said that “there is so much water there is flooding.”

López Obrador has made a point of trying to promote development in Mexico’s impoverished but water-abundant south, but that is far from the United States, Corona’s biggest export market.

One year ago, the Mexican government held a referendum that cancelled permits for a big border brewery built by the company that brews Corona beer, arguing it would use too much water.

Constellation Brands, based in Victor, N.Y., had already partly built the $1.5 billion brewery near the border city of Mexicali, across the border from Calexico, California. Constellation owns Corona, Negra Modelo and Pacifico beers.