The Brundtland report defines Sustainable Development as development that meets the needs of the present without compromising the ability of future generations to meet their needs1.
.There are three elements, namely:

It is important to understand and recognise that each element has an equal standing. This is a critical point, since many commentaries incorrectly assert that balance should be achieved which is plainly incorrect.
Development is an essential part of our community, society, and important for stakeholders. However, there is a clear difference been exploitation and sustainability. Sustainable Development concept pivots round the big picture. Understanding the tripartite relationship between the the three tenants of sustainability demands more thought, planning and consideration.
Furthermore, it is a concept that can be applied at different levels, Governmental, district, organisational and personal.
Whilst considering a particular challenge, personal or corporate, one must consider all the elements related to that decision. For example, one cannot sacrifice environmental issues for the sake of the economy.
Essentially Sustainable Development it is simply commonsense, there is no valid reason to poison the air we breath or our water sources for profit today - where that action leaves future generations with an uncertain future.
There are countless examples of failed sustainability in Hong Kong, with a rich source of failed sustainability examples it is easy to identify the contradictory position, which will help to clarify the ideas behind the concept. Let's look at a couple of recent examples.
Hunghom Peninsular
The proposed demolition of the Hunghom Peninsular PSPS development was certainly not Sustainable Development, failing on both societal and environmental grounds. However, the proposed construction waste handling and recycling plan was one positive aspect.
The owners didn't consider the big picture, financial considerations alone drove the owners to consider demolishing 2700 apartments which have never been occupied.
West Kowloon Cultural District
The proposed West Kowloon Cultural District (WKCD) is slated to be constructed by a single organisation (so called single developer model) and that is not Sustainable. It fails because the single developer model prevents most companies in Hong Kong from actively participating.
Stanley Grove
An existing tree grove in Stanley district was slated for re-development, being converted into a tourist coach park. The land, adjacent to the renovated Murray House complex, was already covered with hundreds of mature trees. The proposal included removal of existing trees and replacing them with new trees. It just doesn't make sense - does it?
Let's dismiss this a myth. Sustainable Development is not a vehicle for closet environmentalist's to hold govern society. Sustainable Development is pro-business, encouraging stakeholder growth and prosperity - not an environmentalist mantra.
Sustainable Development is defined as development that meets the needs of the present without compromising the ability of future generations to meet their needs.
One could easily imagine an environmentalist landing in Hong Kong is the late 1800's, and declare "the barren rock" as an area of special scientific interest, demanding an outright ban on development. Whereas Sustainable Development proponents would have set-out a master plan considering the needs of the people, apportioning land for all needs.
Sustainable Development as a principle, promotes and encourages stakeholder prosperity.
Sustainable Development may seem an insurmountable task, yet every individual effort will make a difference. At first, the benefit of your personal effort might not be perceptible, however history has shown that perseverance is indeed rewarded.
The effect accumulates, reinforcing the practice of Sustainable Development, these practices become customary even mundane. At some point in time, the tipping point, critical mass is achieved, where society as a whole embraces the idea or concept, and reflected as a standard for the whole of society.
Lets us consider a simple example, vehicle seat belts:
HKSDF is a non profit organisation devoted to promoting Sustainable Development in principle and practice - http://www.hksdf.org.hk
Sustainable Development will, at some point in time, be automatic and mundane concept. However, that is not an excuse to overlook this important concept.
Hong Kong is a densely packed city with nearly seven million residents packed into approx. 1000 square kilometres. Hong Kong will be nice when it is finished - an ironic view of a city seemingly continuously under the jackhammer .
Seriously, the future needs careful consideration today. Where land is deemed scarce and further reclamation questionable, it is obvious that the expanding population will require land for residential accommodation development and whilst there is no immediate shortage, Government planning will take years of preparation.
Ultimately the land supply will inevitably will diminish, hence pressure will be brought to bear on the green belts.
Although solutions are not needed today, careful planning, coupled with increasing development density could accommodate a respectable rate of growth without sacrificing future prosperity.
http://en.wikipedia.org/wiki/Sustainable_development