If we can say that cities are yellow, we would also have to admit that cities everywhere are getting less yellow. Universal access to spaces and services is now increasingly restricted. This is especially the case in the new spaces of the city, and the new types of services, infrastructures, and technologies that are made available there. In addition, as urban populations get more diverse, many city residents themselves prefer not to share, at least not with everyone.

Much of this process is bound up with ideas of choice and quality. Many people command better quality and higher specification, and are willing to pay for it. Customised services, ‘premium’ buildings and developments, and cutting-edge infrastructures are designed for and marketed to demanding business interests and socio-economic groups. These features tend to accumulate in the same new and regenerated commercial and residential districts of our cities.

These areas are, however, very often subtly – or sometimes very explicitly – separate. Frequently the benefits of increasingly sophisticated urban life are ring-fenced for specific categories of people, effectively partitioning what could be the most universally ‘yellow’ areas. Such parts of our cities are increasingly globally connected, through transport links, information technology, and the business practices of fashion, franchising, and branding. Meanwhile they are often becoming less connected to the neighbourhoods directly adjacent. This could be thought of as the ‘Balkanization’ of the city.