Des risques « naturels » aux politiques urbaines à Mexico

Mexico City is located at an altitude of over 2 000 metres where it occupies an attractive but hazardous site hemmed in by the Sierra Madre and volcanic mountain ranges.The site is one of the most disaster-prone locations in the world, threatened by a combination of natural hazards, poorly controlled technological hazards created by the city’s heavy industry, pollution – particularly air pollution and diminishing local resources, the most seriously threatened being water. Since the devastating earthquake of 1985, Mexico’s planners have attempted to address the questions of hazards and sustainability in the city’s new urban development policies. But although the various hazards have been clearly identified and appropriate responses determined, the latter have remained for the most part unimplemented. A normative approach that does not take into account the entire metropolitan area but uses the peripheral zones to improve the sustainability of central areas (a kind of imported sustainability at the metropolitan scale) explains this situation. Local and national players regularly attempt to address the many hazards to which the city is exposed but ultimately seem to make very little progress. Their situation is a little like that of Sisyphus trying to push his rock up the hill, but in this case it is not really the rock that is the problem but rather the slope. In other words, the real problem for Mexico City is the substrate composed of local representations and uses of space that underlie the very foundations of Mexican society – and on which the rock rolls