Water is a vital element, as it is in it where life originated. Between 60 and 99% of the components that make up all living beings are composed of water. Likewise, 75% of the world is made up of water.
However, one of the contradiction is that the sea water due to the large amounts of salts containing, can not be metabolized by terrestrial living beings.
Today, humans in an effort to find a "better life", "to meet their needs" and "to improve their social life", has led to a change in the environment, which has brought great result atmospheric changes (melting icecaps, floods, landslides and droughts, among other catastrophes of global climate change). So that now water can leverage and people increasingly consume less. A very revealing and alarming example is that we live in the City of Mexico, where there is a great lack of water in different delegations as Iztapalapa and Iztacalco and is even more ironic that at the same time, on the coast of Mexico, as in warrior and Veracruz where entire villages have been razed by severe floods also have a lack of potable water.