“The first slums were in Europe”

The term ‘slum’ was coined in London in the 19th century. The east of the city was full of slums, which the upper classes of the metropolis even visited as part of a slum tourism operation that included guided tours. Today, in Europe we like to pretend that we no longer have slums. Why?

It is true that the first slums emerged in Europe during industrialisation. Rapid population growth meant that people in many parts of the cities suffered from extreme poverty and had to endure appalling sanitary conditions. The number of slums in Europe has decreased significantly during the centuries of struggling for more political and social justice and less inequality. But they still exist. According to UN estimates, over fifty million people in Europe live in such settlements today. In many cases, they are just less visible than they used to be.

“According to UN estimates, over fifty million people live in these settlements in Europe”

Can you give a specific example?

In a report for the European Commission in 2023, I identified various types of informal settlements or slums in the EU: These include, for example, vast refugee camps. For a long time, the most well-known example was the so-called ‘Jungle of Calais’, a tent city that was home to over 8,000 people in 2016. Moria, the refugee camp on Lesbos with 12,000 residents at times, was next to trigger debate.

Such settlements are designed as a temporary solution. But because the situation is so hopeless for many, they become long-term settlements and the terrible conditions prevail. Another example is the informal settlements of Sinti and Roma and other marginalised groups in Western and Eastern Europe. In Romania, the mayor of Baia Mare had the local slum sealed off by a wall in 2013 instead of integrating it into the city. EU member states often do not even mention that they have a problem with slums or informal settlements when conducting surveys. The responsible authorities prefer to look the other way rather than take action or even tackle the causes. 

So informal settlements are also a problem in Western Europe.

Yes, Cañada Real in Madrid, for example, is notorious as the largest informal settlement in Western Europe with a population of around 8,000. Many Roma live there, but not all the population is Roma. It is dominated by violent drug cartels. Of course, the scale of the settlement is smaller than those in Asia or Africa, for example, where settlements often number hundreds of thousands of inhabitants. But the structures of marginalisation are ultimately the same, and extreme poverty also prevails here.

People live in improvised, undignified and dangerous accommodation. Camps and informal settlements of refugees and homeless people are regularly evicted. The authorities evict inhabitants overnight without offering them an alternative. The last time human rights organisations documented this type of crackdown was at the Olympic Games in Paris in the summer of 2024. But people continue to act as if there is no problem. 

“In Europe, as elsewhere, slums arise from marginalisation and extreme poverty”

In addition to migration, displacement and the exclusion of marginalised ethnic groups, what other factors drive the formation of slums in Europe?

In Scandinavia, for example, there are social housing estates that are now so run-down that mould is everywhere, houses are falling apart and are no longer safe to live in. The economic crisis and overpriced rents are leading to more and more ‘deprivation of housing’ in Europe, as we say in urban studies, i.e. creating living conditions that are increasingly precarious and inhumane. Many people in need are making do with alternatives that are not intended for long-term residences, such as moving into campers, sheds or tents. The boundaries between what we traditionally understand as ‘normal’ housing and what we consider to be slums in urban areas are often blurred.

You are an expert in the visualisation of geodata and the mapping of informal settlements. How can maps help to improve living conditions in such places?

One example is a slum in Kenya where, by analysing the data, we were able to see that huge rubbish dumps were causing water to back up, leading to flooding. As a result of the visualisation, the waste has been cleared away. Worldwide, mapping informal settlements is a major challenge because these places are often not properly recorded due to their illegality, residents are regularly evicted and so on.

Also in Europe, hardly anyone cares about this data, even though the eleventh Sustainable Development Goal of the United Nations states that we must ensure decent and safe housing for all. This includes making housing affordable. Mapping is an important step in the right direction. It shows us what is needed in an informal settlement, how it is evolving and whether it is threatened, for example, by the increasingly frequent and catastrophic effects of climate change. That's why I co-founded a global network called IDEAMAPS. There, in close cooperation with local people and scientific institutes, we collect data on relevant settlements and then visualise it. 

How do you ensure that the population's privacy is not violated by satellite data during the mapping of slums?

At IDEAMAPS, we pixelate everything over 100 by 100 metres. This guarantees that we can collect important data without exposing anyone. However, visualisation in and of itself is of central importance. Because I think that in Europe in particular, there is often a lack of understanding of how dangerously many people live in urban areas. Worldwide, we need to do more to investigate living conditions in these places and boost awareness of the issue rather than sweeping it under the carpet.

Interview by Morgane Llanque