Sustainable development (SD) is development that “meets the needs of the present without
compromising the ability of future generations to meet their own needs” [1]. The definition also
includes two facets: First one is about the concept of 'needs', in particular the essential needs of
the world's poor, to which overriding priority should be given; and second one is the idea of
limitations imposed by the state of technology and social organization on the environment's
ability to meet present and future needs.