Istanbul is the largest city in the Balkan region. It is an ancient, but rapidly growing city that straddles Asia and Europe along the Bosphorus strait. 95% of Istanbul is urbanised, mainly in response to overwhelming housing demand from inward migration. The formal city covers 1,839 km2, an area slightly larger than London but with 30% more people. But its informal bounds are ever-expanding as the city grapples with a combination of suburban sprawl and increased inner-city living.

In past decades pressing urban needs have often been met through informal means. This is particularly true of the housing sector, where gecekondu (‘built overnight’) squatter settlements on the city’s edges have been legitimised. In contrast, more recent residential developments take the form of gated communities.

Istanbul’s metropolitan government has recently acknowledged the need for more comprehensive planning by establishing an urban planning department. The intention is to put in place a structured process of project negotiation as well as more efficient administration of public works projects.

Co-ordinating transport is another key challenge. Over two-thirds of daily journeys in Istanbul are made on an already over-burdened public transport system; under a third are conducted by private car. Public transport infrastructure struggles under the weight of an ever-expanding population. Nevertheless, public policy has had some success in encouraging car-free travel alternatives, and improvements to the current transport system are planned, including a new tunnel beneath the Bosphorus strait linking train networks on both continents.