The Azoteas Verdes (Green Rooftops) project, of the municipal government of the Historic Center of Mexico City, aims to improve household ecology by planting bushes and gardens on buildings' rooftops. The first will be completed in four months. It is an effort to design cactus and vegetable gardens for the area, one of the most polluted in the city, as a means to reduce the costs of waterproofing roofs, improving sound and heat insulation, thereby reducing household energy expenses.

The project “is a good, sustainable idea at a very low cost. It is productive, not just decorative, because food can be grown,” Hazett Cervantes, director of the Botanical Garden of the non-governmental North American Center for Environmental Information and Communication, told Tierramérica.

These gardens will capture an estimated 115 kilograms of contaminating particulate matter annually and produce oxygen in a quantity equivalent to what 110 people would breathe in a year.