For decades we have seen how pollution has been associated exclusively with industry, cities and the polluting gases emitted into the atmosphere, giving rise to a simplistic view which considerably reduces the factors and consequences of environmental impact. Do you remember the greenhouse effect? Well, it is still here. However, it is no longer featured in as many headlines as it used to in the late 1990s. Environmental sustainability, as a concept, has broadened our vision of the challenges that cities face today.