Peri-urbanization, illegal settlements and environmental impact in Mexico City

In 2005 Mexico City had just under 20 million inhabitants in the whole metropolitan area. Although over the last 20 years the city has registered a slower population growth, its urban area continues to expand. The particular problem with the expansion to the south is that urbanization is invading a so-called Preservation Zone (Suelo de Conservacion) that represents a territory subject to preservation given its ecological value in terms of climate regulation, water recharge, forest communities, agricultural cultivation, and hilly landscape. In this particular space, there is a process of diffused urbanization with very low densities in the Preservation Zone. In recent years it has been possible to identify a high number of illegal settlements of low income populations within its limits. This is a continuous, small-scale process, but in the medium and long term it means a significant loss of land with high ecological value. This process happens despite land use planning regulations being in existence since the late 1970s. From 1970 to 1995 just over 10 thousand hectares were lost including irrigation land and forest areas. The analysis includes, the dynamics and main patterns of urbanization in the Preservation Zone, the description of planning norms, and a precise measurement of illegal settlements. The paper concludes that this peri-urban process shows, a marked environmental damage, lack of effectiveness of planning norms and of increasing living standards of the poor, all of which show an ineffective urban governance, that does not contribute to sustainability in the Preservation Zone and in the city in general.