In 2015, the UN General Assembly approved the 2030 Agenda. There was an agreement on 17 Sustainable Development Goals (SDGs), the purpose of which was to reverse development patterns around the planet. Cities, as population agglomerations and production centres, are directly challenged actors. The growth patterns followed in recent years show a clear explosion of the urban fabric, and an unprecedented land occupancy. So much so that certain degraded urban sectors are being abandoned to the detriment of new construction sectors located in the urban periphery. The connotations of this phenomenon are multiple, but it is important to focus on the unsustainability of an urban growth model based on urban development, land occupancy and transport infrastructures that have not been planned in coordination with these urban projects. Based on the foregoing, this article reflects on the externalities of this phenomenon, and raises some reflections to help transition towards a more sustainable city model.