Sustainable development refers to the ?Development that meets the need of present without compromising the ability of future generation to meet their own needs? (United Nation [UN], 1987). Sustainability stands on three pillars- Environment, Economy and Society. Development activities incorporating all these pillars are considered to be sustainable. However urban centres are considered to be engine of growth and since majority of population of world live in these urban areas it is vital that these need to be sustainable for sustainability of human race. The goal of sustainable urbanization us to improve the living and working environment of the residents of urban areas in sustainable manner (Joshi, 2011, p.68) but if urban development is examined with reference to it, urban development in Nepal have not considered sustainability properly.

Cities have immense potential for sustainable development (Joshi, 2011). At present context from the perspective of urban development of Nepal, it is garnering economic benefit to the country that is it contributes up to 60% in the Gross Domestic Product (GDP) of the country (Sharma, 2012). However it is weakening the social bonds and causing environmental degradation. An example could be Kathmandu valley itself as till 1994 except for sanitation the environmental quality of the valley towns was excellent (HMG/UNDP, 1994, as cited in ADB, 2006). Also IUCN in 1999 stated that due to rapid urbanization cultural heritage sites and the monuments of Kathmandu valley is fast deteriorating (as cited in ADB, 2006).

Since Kathmandu valley is still the most urbanised area of the country it can be taken as an example of consequences of urbanization pattern in the country. 66% population of Kathmandu district, 48% population of Lalitpur and 53% population of Bhaktapur district live in the urban area (CBS, 2011). In comparison to other urban centres of the country accessibility of physical infrastructure is high however quality of those services is questionable. For instance number of hospitals in the valley is increasing rapidly along colleges and other educational institutions however quality of service in these is still to be assessed. ?Number of hospitals and educational institutions has definitely increased however they are more business oriented rather than providing service? (Deepak Parajuli, Personal Communication, 23-05-2013).

Environmental situation (Overview):

Considering Kathmandu valley as an example of most urbanised part of the country, the degree of development and its impact upon environment can be studied. Consequences of rapid and unmanaged urbanization can be experienced by each individual visiting the urban centres of the valley.

The valley has literally turned into a concrete jungle for which good arable and green spaces has been used up.  During a period of 80 years land use pattern of Kathmandu has changed significantly with 54% residential area in 2000 which was previously 8% only in 1920.