A few decades have passed since we first became aware that the world is a single system, integrated and synergetic but also small and fragile. We now know, for the first time in human history, that the majority of people on the planet are living urban lives. Despite the current global recession, projections tell us that this trend will continue. Seventy-five per cent of the global population is expected to concentrate in cities by 2050 – in megacities of several million people, or massively urbanised regions stretching across countries and continents. This relentless pace of urban change is likely to be fuelled by the environmental impacts of climate change, with more people – climate change refugees – abandoning exposed agricultural areas in favour of the relative protection and promise of the city.

The scale of today’s urban context is difficult to grasp. While only 186 million people lived in cities of over a million or more in 1950, this figure reached one billion in 2000 and will grow to 1.8 billion by 2025. For megacities of ten million or more, the increase is twice as fast: from 23 million in 1950, to 229 million in 2000, and 447 million by 2025. Yet whereas Europe, North America and Oceania became mostly urban before the 1950s and Latin America during the 1960s, Asia will only hit that mark in 2024 and Africa in 2030.

Even more challenging is the fact that today’s urban growth is concentrated in areas where poverty and deprivation are rife, where cities have the potential to either integrate or separate. According to the United Nations, Mumbai – India’s dynamic powerhouse – is set to overtake Tokyo as the world’s largest city by 2050. Shanghai, meanwhile, continues to grow at a breathtaking pace in both height and breadth with more than 10,000 buildings over eight storeys high compared to just over 100 such buildings only 25 years ago. But rapid urbanisation is not always paralleled by the exponential economic growth and comprehensive infrastructure investments of the Asia Pacific region. Nowhere is this more true than in the two megacities of sub-Saharan Africa: with each passing hour, Lagos will add 67 new residents and Kinshasa 34 by 2025. Post-apartheid Johannesburg and Cairo face different problems. While Johannesburg struggles with crime, fear, segregation and AIDS, over 60 per cent of Cairo’s population lives in informal settlements and there is only one square metre of open space per person. Each Londoner, by contrast, has access to 50 times that amount.

The information contained in this data section summarises research undertaken by Urban Age since 2005. It includes an overview about urban trends in Istanbul and places it in a comparative context with other world cities, including New York, Shanghai, London, Johannesburg, Mexico City, Berlin, Mumbai and São Paulo. By investigating differing patterns of urban density, transport and governance, together with a wide range of social and economic indicators, the information provides unique insight into the DNA of cities today.

Behind the statistics of global city growth lie very different patterns of urbanisation, with diverse spatial, social and economic characteristics that dramatically affect the urban experience in cities around the world and in addition to standard measures of population growth and density, economic weight and transport use, the Urban Age has assembled data from a range of official sources on energy consumption to global CO2 emissions, allowing a preliminary assessment of how these nine world cities compare to each other on key performance indicators.

A graphic summary of these results offers some striking differences, especially when it comes to their speed of growth. While São Paulo has grown nearly 8,000 per cent since 1900 and London by only 16 per cent (having experienced its major growth spurt in the previous century), it is Mumbai that is now growing the fastest of the nine with 47 new people expected to move into the city each hour by 2025. London, instead, will only gain one person per hour and Berlin will remain static. These trends mask different patterns of age distribution: close to a third of the residents of Mumbai, Johannesburg, São Paulo and Mexico City are under 20 years old, while in Shanghai and Berlin the younger generations shrink to 20 per cent or less.

Patterns of habitation also differ significantly. The high residential densities of New York’s Manhattan (53,000 people per km2) are nearly doubled in Shanghai (96,000 people per km2) and Mumbai, where, despite the fact that most people live in low-rise structures, residential densities reach over 100,000 people per km2. By contrast, Berlin peaks at only 21,700 and London struggles to reach 17,200. São Paulo, Johannesburg and Mexico City prove to be the more dangerous places to live – ranging from 13 to 21 murders per 100,000 people – while Istanbul and Mumbai have very low levels of serious crime with only 3 murders per 100,00 people, slightly worse than Berlin and Shanghai. These findings are paralleled by the level of income inequality indicated by the GINI index – a measure of income distribution with a higher number representing greater inequality – in each of these cities: Johannesburg, São Paulo and Mexico City are the most unequal cities, followed closely by New York, with London being the most equitable. Despite the fact that Mexico City’s per capita income is less than a third of New Yorkers’ (US$ 18,321 versus US$ 55,693), residents of Mexico City own nearly twice as many cars (360 per 1,000 people versus 209) and use roughly the same amount of water per person as Londoners (324 litres per day). While Johannesburg, London, Berlin and Mexico City contribute similar levels of CO2 emissions per person, the number doubles in Shanghai, where over 10,000 kg per person are produced every year owing to the presence of heavy manufacturing industry in its vast metropolitan region. This can be contrasted to Istanbul: with close to 38 per cent of its workforce in the manufacturing sector, the highest of the Urban Age cities, it only produces 2,720 kg of CO2 per person. Mumbai’s residents contribute only 371 kg per person – less than ten per cent of that compared to residents in other global cities. Given India’s economic and population growth rate, the future choices that cities like Mumbai make in terms of sustainability will have a dramatic impact on the ecological balance of the planet.

All cities, except for Berlin, punch above their weight in terms of the economy. Istanbul, with 17.8 per cent of the national population, contributes 22 per cent of Turkey’s GDP, while Mexico City’s 8.4 per cent drives Mexico’s economy with 21.5 per cent of national GDP. In New York City the figures comprise a smaller share: the city delivers only 3.3 per cent of the United States’ GDP while hosting 2.8 per cent of the nation’s population. Londoners, on the other hand, contribute over 16 per cent to the UK’s economy, but its residents are faced with the highest public transport costs across the sample, with the typical price of a journey costing three times more than in New York and 37 times more than in Mexico City or Mumbai.

* Estimated

** London and Johannesburg represent the current population in the administrative city as they do not have a corresponding metropolitan region.

*** PM10 refers to the amount of pollution in each city’s atmosphere. This index has been developed by the World Bank to measure the annual average concentration of heavy particulate matter in micro grams per cubic metre.

This data has been derived from various official statistical sources, including the United Nations Statistics Division and census for each city and country. Complete data sources available at www.urban-age.net The ‘DNA of Cities’ presented above is adapted from originally published work in The Endless City, Phaidon Press (2008).

Cities are engines of growth, centres of consumption and production. They promote economic vitality, cultural exchange and social integration. However, urban economies are also fragile. Their high reliance on the service sector makes them vulnerable to financial instability, as the current global recession shows. Yet, due to the high concentration of wealth and related consumption patterns of urban lifestyles, cities contribute to a high percentage of global CO2 emissions − up to 75 per cent according to some estimates – the main component of greenhouse gases. As these gases are emitted much faster than they can be absorbed by oceans, plants and soils, they have been building up in the atmosphere, trapping more and more heat. As a result, global mean temperatures have risen dramatically; by 0.76 °C compared to pre-industrial times. Higher temperatures increase the risks associated with rising sea levels, flooding, desertification and droughts. In 2002, the World Health Organisation estimated that 150,000 people died every year from the consequences of climate change, a figure that has been recently adjusted to 300,000 to reflect the fact that illness spreads much faster in warmer weather. These initial estimates were based on a warming of just 0.6 °C. Yet if these greenhouse gas emission trends continue, global temperatures could rise 6 °C by the end of the twenty-first century.

However as can be seen in the map of flood risks below, the impacts of climate change are not evenly distributed across the globe. Residents of low income countries are often more vulnerable, partly because of their exposed geographic locations but also because they lack the resources to retrofit their environments to adapt or mitigate such risks. As is highlighted by the pie charts on the opposing page, developing countries emit far less carbon emissions than developed nations. Thus there is an inverse relationship between a nation’s role in accelerating climate change and its exposure to the environmental impacts associated with climate change. This can also be said of cities. With the exception of Shanghai and Mexico City, the urban centres that are most at risk tend to emit less CO2 per capita than cities in high income countries. Today, cities such as São Paulo and Mumbai do not damage the environment as severely as their more advanced counterparts, yet they are not able to prevent and mitigate the risks. The energy-intensive forms of development that cities of the global South are pursuing – increased car dependency, segregated planning, out-of-town shopping centres, reliance on fossil fuels and air-conditioning – will invariably increase pollution levels over time.

When it comes to linking urban development to climate change, city dwellers are more efficient than their national populations. In the nine cities under investigation, only Shanghai and Mexico City have higher per capita CO2 emissions than their respective nations. Well designed cities, which feature a dense urban fabric connected by an efficient public transport system, have the potential to play an increasingly critical role in balancing the equation between resource consumption and global sustainability. As long as sprawl is contained and the natural environment is protected, cities could have a positive impact on global ecology. But this can only be brought about through investments in green technologies and more energy-efficient buildings fostered by environmentally conscious policies, economic incentives and a change in lifestyles.

These maps identify the built-up area, shown in grey, of nine world cities drawn to the same scale (200 x 200 km). They have been drafted using analyses of satellite images that capture the precise location of any built form or structure on the ground. They give an accurate and up-to-date account of the real shape of the urban footprint in these metropolitan regions today, offering a new perspective of settlement patterns across a range of global cities.

Two phenomena immediately stand out. The first is the clear misalignment in some cities between the administrative boundaries and where the majority of people live and work, highlighting the fact that cities are dynamic while urban governance is static. As cities have grown, many municipal boundaries look increasingly outdated and unrepresentative of the functional extent of the city. While this is not the case for Istanbul and Shanghai, whose vast administrative boundaries encompass nearly all the continuous built-up area, most of the Urban Age cities spill out beyond their municipal boundaries. The extreme cases are Mexico City, New York City, São Paulo and Mumbai. In these four cities, the administrative cities contain only 44, 46, 57 and 65 per cent respectively of their metropolitan populations. This means that in Mexico City, the Mayor of Mexico DF is responsible for only 8.8 of the 19 million people who are a part of the city’s functional metropolitan region (which includes parts of the State of Mexico). On the other hand, London demonstrates the effectiveness of its ‘Green Belt’ – revealed by the white circle around its periphery – that has acted as an effective urban containment boundary for the last 50 years, without hampering its integration within the densely-populated South-East region. Berlin and Johannesburg also display a closer correlation between built-up area and municipal boundaries.

The second significant finding is the extreme variation in ‘land-take’ of cities in response to their geographic locations and differing population densities. Mumbai, with a population size comparable to São Paulo and Shanghai, is densely packed in a relatively small footprint within its natural contours between the Arabian Sea and the Thane Creek. São Paulo, on the other hand, has been able to expand horizontally along its high plateau, encroaching on natural features and water reservoirs to the South. The same pattern can be observed in Mexico City and in New York’s metropolitan region. Shanghai reveals a pattern of organic ‘satellite towns’ along radial routes feeding to the heart of this Asian megacity, with the bulk of development in central areas close to the Huang-Po River. Historically, Istanbul’s footprint has grown inwards from the European and Asian edges of the Bosporus strait and now covers around 16 per cent of the Province.

These graphics show how Istanbul’s built-up area has expanded from the pre-fifteenth century up to 2000. In the late Ottoman era, the city started to develop from the historical peninsula on the Bosporus. By 1950, the built-up area expanded along the East-West axis, covering most of the Marmara Sea’s coast on the Anatolian side. Between 1950 and 1970, the first wave of large-scale migration brought with it gecekondu (informal) settlements occupying large areas on the peripheries. Industrial development continued to promote migration, and by 1990, the forest and water reservoirs began to be threatened by uncontrolled development, further fuelled by the opening of two bridges spanning the Bosporus. In 2000, the built-up area spread even further outwards on the European and Asian sides. A significant portion of this recent expansion can either be tied to the development of gated communities for the wealthiest of the city’s population or to mass housing for its middle classes.

Istanbul

Istanbul’s government functions within a unitary national framework with ‘federal’ ministries, based in the capital Ankara, providing health care, primary education, policing, some housing and transport, among others, in the city. The ministries’ involvement in city affairs is coordinated by a governor, who is directly appointed by central government. Some central governmental bodies such as the Mass Housing Administration have direct links to the Prime Minister, while the Transport Ministry’s involvement in Istanbul is coordinated by the Governor of Istanbul. One of the most important political figures in Turkey is the Metropolitan Mayor of the Istanbul Metropolitan Municipality (IMM), who is directly elected by the city’s population for a five-year term and shares executive power with a Municipal Council formed by selected members of the city’s 39 District Municipalities and their District Mayors. District Mayors are also directly elected and lead the District Municipalities. The IMM enjoys extensive powers and a significant budget for citywide planning, transport, housing and environmental services, among others.

The governance of Istanbul does not, however, happen only at the municipal and central levels. Partly to comply with the European Union accession process, Turkey recently created the Istanbul Development Agency, one of 26 regional bodies assisting coordination between the municipal and central bodies as well as civic institutions for budgeting and planning of large-scale urban projects. In addition, there are provincial authorities for each of Turkey’s cities which have significant areas of responsibility, including masterplanning, although in Istanbul this responsibility has been transferred to the IMM.

In 2004, the IMM’s administrative boundaries were extended to coincide with the larger provincial boundary. The administrative boundary increased threefold, from an area of 1,831 km2 to 5,343 km2, one of the largest municipal footprints in the world. As a consequence of this boundary overlap between the Provincial authority and the IMM, the Metropolitan Mayor’s power has increased considerably while the powers of the Provincial Special Authority have been reduced.

In an effort to enhance coordination between the various departments of the Metropolitan Municipality to help develop the city’s masterplan, the Mayor set up the Istanbul Metropolitan Planning and Design Centre (IMP) in 2005. The IMP was established through funding from BIMTAS, a public private partnership that serves as an affiliate company of the Metropolitan Municipality. Initially consisting of 400 experts, academics and key municipal members, the IMP has reduced in size in recent years.

At the local level, the administrative geography of the Istanbul province was rearranged in 2008 to have a single level of subdivisions or districts (ilçe). The number of districts has increased to 39 through the consolidation of 41 first-level municipalities into eight new districts and the merging of the former district of Eminönü into Fatih (now the only local district authority exerting power over the entire historical peninsula).

São Paulo

São Paulo’s city government is led by a directly elected mayor, and São Paulo State is led by a directly elected governor. The mismatch between São Paulo’s municipal boundaries and the extent of the city requires these two levels to work very closely together. In terms of transport, the city government controls part of the urban transport system while the state is responsible for integrated transport planning across the metropolitan region. With respect to housing, both levels have housing enterprises with specific responsibilities. As concerns security, the military and civilian police forces fall under the State’s authority, while the city maintains a local police force. In the field of education, responsibilities are divided between the state and the city governments, while an institutionalised management structure exists for health care that distributes responsibilities among federal, state and local governments. A third, decentralised level also exists under the municipality: 31 subprefeituras are the main point of contact for the population. They manage local public services and have some planning and transport responsibilities.

New York

New York City’s government operates within a legislative framework determined at state level (the Federal State of New York). Federal government in the United States has no direct powers to direct or legislate for the actions of individual cities, though federal agencies operate in all parts of the country. However, the state level of government is important both as a legislator and because of its powers of budgetary supervision. The state also runs the major transport systems, is co-owner of the city’s airports and oversees some elements of the city’s economic development. Within this framework, the city is powerful by international standards: the Mayor of New York is one of the most important elected officials in the United States. Even so, local legislation is the responsibility of the City Council. New York City government is responsible for public education, public hospitals, social care, the environment, planning and some local transport. There are five boroughs, each headed by an elected Borough President which has rights to be consulted though they provide no services. There are also 59 Community Boards which provide advocacy for neighbourhoods.

London

London’s government operates within a relatively centralised, unitary state. Several central departments have responsibilities within the city, including health care, the regulation of commuter railways and as final arbiter for major planning decisions. Central government also has a number of regulatory powers over the mayor and the city’s boroughs. The Mayor of London is the elected executive for a number of major city-wide services, notably public transport and spatial planning. The mayor is overseen by an elected, non-legislative assembly. There are also 32 elected borough councils whose responsibilities include schools, social care, the environment, local transport and local planning. The City of London, the UK capital’s financial and business hub, has the powers of a borough but also several additional responsibilities. The government of London has been reformed on several occasions since the late-nineteenth century, most recently in 2000 to allow Londoners to vote for a mayor for the first time in their history.

Mumbai

Mumbai’s government involves interventions at national, the state of Maharashtra, and local levels. The national government has a number of powerful departments that provide services and resources for the city. There is a significant level of state government, headed by a Chief Minister, which operates many services within the city, including roads, housing, education, health care, environmental services and policing. The city government is headed by an elected mayor with limited power. The real executive power lies in the hands of the Municipal Commissioner and the Secretary for Special Projects, both civil servants appointed directly by the Maharashtra State government. The state government has constituted a Metropolitan Planning Committee for the Metropolitan Area as required by the Jawaharlal Nehru National Urban Renewal Mission (JNNURM). There is significant overlap between responsibilities at state and city levels. Overall, the city government is relatively less powerful than the state, as required by the JNNURM.

Urban density is illustrated below in terms of the number of people living in each km2 of a 100 x 100 km urban area. Density is largely driven by topographical constraints and the location of public transport and other infrastructure, but also by each city’s inherited traditions of urban planning and development. While high density is sometimes associated exclusively with poor and overcrowded urban environments, it can also enable a higher quality of life and reduce the environmental impact of cities by facilitating walking and cycling. In doing so, high density urban areas can enhance a city’s vitality and make the provision of public transport and other amenities more viable.

Urban Age cities demonstrate a wide range of differing density patterns – from the very high densities in the centres of Mumbai and Shanghai to the much lower density development patterns of Berlin and London. Johannesburg shows limited areas of high density set around a downtown that no longer has a residential population, in the midst of a very low-density sprawl. The pattern displayed by New York, on the other hand, shows how the constraints of waterways drive densities that rise to a ‘spike’ in Manhattan and parts of the Bronx, Brooklyn and Queens, while the rest of the metropolitan region has a lower density.

São Paulo is multi-centred and similar in its overall density pattern to Mexico City. This is a striking comparison given that the two cities are very different in terms of their urban form − São Paulo’s skyline is dominated by high-rise apartment blocks, while Mexico City’s is consistently low-rise. It proves that urban form and density are different concepts. Furthermore, their similar density profiles shows how high-rise buildings do not necessarily create higher density in comparison to more tightly planned low-rise development, especially when individual towers are surrounded by large areas of motorways or unused space.

In Istanbul, density levels are high, particularly when compared to other European cities. The city’s peak density of 68,602 people per km2 is well above Manhattan’s extreme, and the average within a radius of 10 km is at least 30 per cent higher than that of any of the other American and European Urban Age cities. Istanbul also displays a distinct difference between the European and Asian sides: while density levels on the European side vary considerably – the highest and also some of the lowest densities within the built-up area can be found here – the Asian side is much more homogeneous and is dominated by mid-range densities around 20,000 people per km2.

Transport infrastructure is a critical driver of urban form, enabling centralisation of economic functions and the accommodation of a growing population along metropolitan rail and bus routes. Where public transport infrastructure is not in place, space-hungry motorways dominate, usually resulting in more sprawling forms of development and congestion as private car use persistently runs ahead of road building. The Urban Age cities offer varying levels of transport infrastructure. The most extensive metro systems have been put in place in London, New York and Berlin, while Istanbul, São Paulo and Shanghai have the smallest public transport network of the nine cities under investigation, leaving many areas without any access to either rail or metro. In Istanbul, construction is currently underway to expand the existing 76 km-long metro network to 231 km by 2015 – although funding to complete this construction is not yet secured. At the same time, 9 km has recently been added to the Metrobus (BRT) to increase the system’s total length to 50 km. The city’s BRT opened in 2007 and operates along a dedicated lane crossing the Bosporus Bridge between Avcılar on the European side, to Kadıköy on the Anatolian side. The extension will continue the BRT from Avcılar to Beylikdüzü on the European side and is expected to increase the current daily use to 1,170,000 passengers per day.

How people travel within cities – the ‘modal split’ – reflects the public transport infrastructure in place, but also local economic development, climate and urban form. Walking dominates as a form of transport not only in cities designed to be pedestrian-friendly, but also as a result of proximities created by high levels of urban density or when access to public transport and private motorised modes is limited. Therefore walking accounts for a massive 56 per cent of journeys in Mumbai, 45 per cent in Istanbul and around 30 per cent of journeys in Johannesburg and Shanghai. Walking also accounts for a relatively high modal share in London and Berlin (20 and 25 per cent respectively). Cycling, on the other hand, is only a significant mode of transport in Shanghai (25 per cent) and Berlin (10 per cent). In all other cities, it accounts for less than 2 per cent of trips.

Around 40 per cent of residents in New York’s midtown Manhattan walk to work and over 90 per cent of affluent business workers use public transport in journeying to London’s financial hub. Shanghai has experienced rapid growth in public transport use, while cycling remains prevalent. Although Berlin has high rates of cycling, its relatively uncongested roads allow high levels of car use – despite the presence of a high-quality public transport system. In some other cities, even where there is a good metro system like that of Mexico City’s, informal transport by mini-bus often dominates, reflecting a mismatch between commuting patterns and infrastructure as well as the relatively high cost of public transport.

 

Nineteenth-century urbanisation was originally a by-product of the Industrial Revolution. Cities are now at the forefront of a new transformation: the shift to a knowledge-based service economy. The nine Urban Age cities are at different stages of this transition. The employment figures presented here show that London and New York are the cities that have advanced the furthest towards this economic transformation, although neither city has an economy based exclusively on financial and business services; retail, leisure, social and personal services continue to be major sources of employment in both cities.

Most of the other Urban Age cities retain 10 to 20 per cent of their secondary sector employment – dominated by manufacturing, industry, and construction. In some cases, a small agricultural sector also remains. Istanbul’s situation closely mirrors that of Shanghai − both cities have retained an extensive manufacturing base (38 and 35 per cent respectively). With respect to the other Urban Age cities, this difference originates from the fact that they are municipalities as well as provinces with large territories (usually in the periphery) where manufacturing and agricultural activities dominate.

The shift towards a service-based economy has farreaching implications for urban government. Office development has created new urban districts often away from the traditional city centre, as is the case in London (Canary Wharf), Mexico City (Santa Fe) and Johannesburg. In some cases, these new developments have been criticised for their sterile quality as well as their lack of public infrastructure, for engendering social segregation, and for draining life from the traditional central business districts.

The success of an urban economy is ultimately determined by its level of inclusion. A city that features high levels of unemployment within delimited sections of its built-up area will expose itself to the pernicious effects of unequal life chances and relative deprivation. The provision of effective social systems and universal education and healthcare are therefore essential elements for fostering a successful and inclusive urban economy. Without these, cities may increasingly operate two parallel economies: one populated by a highly mobile, highly educated elite; the other dominated by people who lack the skills to share in the prosperity that the knowledge economy can bring.

For some 2,500 years, Istanbul has developed and re-developed itself, creating a city of multiple layers which are sometimes complementary and sometimes dissonant in response to its dramatic vertical topography and varied terrain along both side of the Bosporus Straits. Following the decision to make Ankara the national capital in 1923, Istanbul suffered a major decline in population and would not reach the one million mark again until the 1950s. Since then, the population has increased twelve-fold, creating a city of new typologies, new densities and new urban geographies. Rapid urbanisation brought with it the challenge of combining integrated planning with a careful consideration of both the city’s traditional delicate urban grain and the natural resources that have been supplying the city throughout its long history, including its busy waterways. The construction of two bridges over the Bosporus provided an opportunity to further integrate the two continents, but also allowed for an unprecedented intensity of residential development – both informal and formalised. Similar concerns have surrounded the debate over the construction of a third bridge, publically announced by the Mayor in late August 2009. The graphic below illustrates the complexity of some of these challenges by depicting interweaving but varied urban typologies (informal settlements and gated communities) with the city’s vital natural resources, historical monuments and green spaces.

More than many other global cities, Istanbul is a city of extreme typological variation, as can be seen in the aerial photographs on the opposite page. A regular street grid layout dominates the traditional grain in the Pangaltı district, where a strong sense of neighbourhood community pervades, albeit without the former mix of Muslim and non- Muslim populations. Tarlabaşı offers a much more complex spatial picture; formerly the heart of the Pera district, it was cut off from its surroundings in Beyoğlu by the creation of the major Tarlabaşı Boulevard in 1980s. Since then, its houses, once occupied by the Greek community, have decayed through neglect or overcrowding, creating a pocket of urban deprivation cheek-by-jowl with Taksim Square and the city centre.

The Anatolian side offered a vast amount of unspoilt land before it was opened to development as a result of new planning regimes and the construction of two bridges over the Bosporus, in 1973 and 1988. Many of the newer typologies of high-end luxury houses and gated communities started spreading on the hills immediately behind the wellconserved Bosporus shores. Although only about 10 per cent of the population commute daily over the bridges, new residences such as the ones in the hills of Anadolu Kavağı provide a higher quality of life for those with the means to commute between work and home. Gecekondu settlements sprouted in large parts of the city, many near the industrial sites along the Marmara Sea, such as Gülensu in the Maltepe district on the Anatolian side.

The layout of streets, buildings and spaces form the spatial DNA of urban growth, the patterns through which city life can develop and cities can grow. These spatial arrangements are critical to the liveability of cities, to the quality of life that they can offer their residents, to the density that they can accommodate, and to their flexibility in adapting to change and growth.

The images presented here help to visualise the microstructure of urban neighbourhoods, how buildings (in black) and open spaces (in white) come together to create an integrated urban whole. The maps presented here illustrate the relationship between urban form and density in Istanbul in three neighbourhoods – high density, mid-level density and low-density – each covering one km2.

The first neighbourhood is Nenehatun in the Esenler district, located on the European side and boasting the city’s peak density (68,602 people per km2). With a population of over half a million, the district was settled between the 1960s and the 1990s and is composed of densely packed five- to six-storey apartment blocks.

The second neighbourhood is Çukurcuma in the Beyoğlu district on the European side. Separated from the old city by the Golden Horn, this district is the arts, entertainment and night-life centre of Istanbul. It is home to a quarter of a million inhabitants, features a density of 23,383 people per km2 and is mostly composed of historical city blocks.

The third neighbourhood is Acarkent in the Beykoz district, a low-density area in the north-western reaches on the Anatolian side. A newly developed residential area, it features rows of identical detached single-family homes with swimming pools and gardens. At 1,320 people per km2, its urban fabric is 18 times less dense than Çukurcuma and 52 times less dense than Nenehatun.

The map above shows Istanbul in its regional context, highlighting all cities of over a million inhabitants and showing Turkey’s trade relationships with other countries in the region. Istanbul is among the top five largest cities in the region, with all of the other major cities to its east. With the exception of Iran, Turkey does not have significant trade relationships with its immediate neighbours: its major trading partners are Russia, Germany, China, Italy and the United States.

Istanbul

• 1,000 per cent population increase since 1950, the highest of the OECD’s 78 metro-cities.
• 12.7 million people in the area governed by IMM (Istanbul Metropolitan Municipality), over 15 million in the metropolitan region.
• Net migration rate has slowed from 10.76 per cent in 1990 to 0.2 per cent in 2008, compared to a 1.57 per cent projected growth rate between 2008 and 2023.
• Main internal immigration is from the Black Sea and the middle and south-eastern Anatolian regions.
• Istanbul has the highest residential density in Europe: 68,602 people/km² peak density; 20,116 people/km² central area density.
• The city is run by the IMM (Istanbul Metropolitan Municipality), with a directly elected mayor.
• 27 per cent of national GDP, 38 per cent of national industrial output, more than 50 per cent of national service output and 40 per cent of national tax revenues come from the functional metropolitan region.
• 50 per cent higher productivity than the national average.
• 60 per cent of Turkey’s total trade goes through Istanbul.
• 11.2 per cent unemployment rate in 2008.
• 60 per cent of the population works in the service sector.
• 30 per cent of the population works informally.
• 37 per cent of the population works in manufacturing, producing 80 per cent of the city’s exports.
• 50 per cent of housing is or was informal.
• 99 per cent of the population has access to municipal services.
• 6.4 m² of green space per person in the province, compared to London’s 26.9 m², New York’s 29.1 m² and Stockholm’s 87.5 m² but only 1 m² of green space per person within the central built-up area.
• 2.72 tonnes of carbon emission and 383 kg of waste produced per person per year.
• 2,267 kWh of electricity and 56,575 litres of water consumed per person per year.
• 148.2 km of rail, with a further 160 km due in 2015, in the core of Istanbul province.
• 138.5 cars per 1,000 people in Istanbul, 45 per cent of the population walks; average commuting time of 48 minutes.
• 3 murders per 100,000 people but 44 per cent of the population is concerned about security and crime.

Turkey

• Turkey is among the top five fastest growing OECD economies between 2000 to 2008 (measured by GDP at Purchasing Power Parity) alongside Slovakia, Ireland, Norway and Spain.
• 24 per cent of the national population worked in agriculture in 2008, producing 8 per cent of national GDP.
• 27 per cent of the national population worked in manufacturing and construction in 2008, producing 24 per cent of national GDP.
• 50 per cent of the national population worked in services in 2008, producing 58 per cent of national GDP.
• Differences in growth rates among regions in the same country were larger than 6 percentage points in Turkey, Poland, Hungary, Greece and the United Kingdom, suggesting that national performance has been driven by the dynamism of a limited number of local regions. Between 1995 and 2005 Turkey had the largest regional differences in GDP growth of all OECD countries.
• Like Greece and Portugal, 10 per cent of the regions with the highest output contributed to over half or more of the national GDP.
• Turkey has by far the greatest specialisation in construction industry in the OECD countries, followed by Mexico, Germany, France and the UK.
• 95 cars per 1,000 people, the lowest private car ownership rate of all the OECD countries.

This data is drawn from the OECD International Reviews: Istanbul, Turkey and other Urban Age Research.