There is no doubt that the city is the dominant type of human settlement, especially given that the half the world's population is settled in the cities and urban life is the leading form in all environments. Increasing urban population is closely tied to the relocation of the population, particularly the rural abandonment and resettlement in urban areas. With such a rate of migration very soon 90 % of the world's population would live in urban areas. Cities that abrupt and rapid increases have major problems with environmental pollution. The most important element here is the human dimension that must be taken into account. Currently 60 % of the world's population already lives in urban areas, of which 65 % live in cities with more than 2.5 million inhabitants . It is expected that already in 2020 the world population will be 8 billion people.
Sustainable urbanization also need to recognize new spatial models. Urban development couldn't be based on standardized models.
Polycentric urban development is based on the idea of a space where dominate multiple centers. This model begins its development in the 1970s of the last century over decentralization of economic activities, growing mobility of capital, labor and technology progress. Polycentricism refers to the morphology of the urban centers, the composition and the relationship of urban centers in the urban hierarchy.
Polycentric urban development is actually a decentralized urban development. The globalization on the world stage brought networked cities, synonym for capital growth (over-population, over-consumption, over-construction ...). The size of the city is in negative correlation with fuel for transportation. This applies especially to the rural areas which are attached to their cities where people work. That people use cars to pass this distance. One of the ideas is to create an urban environment that will ensure a quality life is with re-creating small neighborhoods like the so-called new urban villages decentralized geographically and institutionally. In this case it is not about city gardens, but geographically dispersed communities that containing houses with enough space around, so people can deal with agriculture and to produce food and other goods necessary for life. The traditional life there would be complemented by new telecommunication related life as a modern model and quality of life.
What is problematic in decentralized environments is the need to bring electricity to the same level as in urban areas which made the whole procedure more expensive. Also, it is unclear how much human dimension has telecommunications and the Internet social activity services that are inevitable for decentralized urban development.
Stockholm is a city recognized as “green and blue city “due to the large areas of greenery and blue sea around the islands on which the city is built. Stockholm today was the result of planning and development strategies of the last century. Since the 1920s, the city began with activities for promotion of affordable and decent houses for their residents. An important part of that strategy was to buy land for development and also to protect the area provided for recreation. In the early 1950s was made the city planning development strategy. New suburban areas were planned along the metro line, thus each suburban area is specific neighborhood with social and commercial core, houses with large population density together with detached houses. Green structure was placed in the form of parks and green areas that divide neighborhoods from each other. In addition, significant was installation of infrastructure across the region, particularly heating, water and sewage. Significant investments have been invested in developing an efficient public transport system based on a network of metro rail lines and connecting suburban communities. Today the city is facing new challenges in creating sustainable modern city. City Council in 1999 approve new urban plan of Stockholm 99. In the process of developing the plan involved a multitude of citizens, organizations, local governments, companies-through public meetings and exhibitions of the plan. It is important to point out that Stockholm has a tradition of dialogue and discussion with citizens about their plans which is planned. As much as is increasing awareness of citizens it is easier to implement program sustainability and preservation of the environment. The idea is to reuse and redevelopment of old industrial areas and changing the existing infrastructure. Several of these areas for development will be connected with high-speed rail system that will enable the development of urban nuclei in places where rail meets metro lines.
The first area of development was the area of the old docks and industry that transformed into a modern part with 8000 apartments and population of 20000 residents. The area should have its own recycling model and treatment of waste and sewage. The plan includes a new subway line and a highly developed network of pedestrian movement and bicycle paths. Another area is Kista ( "wireless Internet Valley " ) where are placed significant leading companies in the telecom and Internet market and the Nordic world , and the largest pharmaceutical and biotechnology companies with research centers. In Stockholm 70 % of the population used public transportation to get to work from their residence in suburban areas.
The possibilities for developing are specific for each city and have to be established in terms of the context and the region. Urban development should be conducted in cooperation with the public and community, social priorities, the establishment of urban form and care for the local environment. Residents should be encouraged to build cheaper and healthier houses and flats for housing. Cities have to plan their expansions in order to meet the emerging needs of the expanding residential areas, spaces for sport and recreation spaces for playgrounds and space for agricultural production.
