Barrera Aguirre and his daughter, Mixtli Barrera Fernández, at their family’s chinampa, the strip of land they farm. ‘If these problems are not fixed, our history, my family’s history, is going to end. Apart from losing this historical memory, the city itself would also be lost because there would no longer be water,’ he says. ‘The opportunity to have this land so rich, so fertile, to produce food would also be lost, and we would be talking about a possible collapse of Mexico City. But we still have time’