The Barcelona Institute for Global Health (ISGlobal), a centre supported by the ’la Caixa’ Foundation, has unveiled a new tool: the Healthy Urban Design Index (HUDI). The HUDI is a composite index that evaluates 917 European cities based on 13 indicators connected to peoples’ health and well-being and divided into four domains: urban design, sustainable transport, environmental quality and green space accessibility. The HUDI is the result of scientific work published in The Lancet Planetary Health. The data for all cities is publicly available on https://isglobalranking.org/hudi/.
In order to make the cities comparable, they have been grouped into five categories according to the number of inhabitants: large metropolitan, metropolitan, medium and small-sized cities and small towns. The 13 indicators assessed include urban compactness, housing density, walking, cycling and public transport infrastructures, air pollution levels, capacity to mitigate and manage heat, and accessibility of green spaces. The index assigns a score between 0 and 10 for each of the indicators analysed and establishes a combined HUDI score.
Small cities lead the HUDI
Generally, the category with the highest HUDI scores is small-sized cities, which includes all European cities with a population between 50,000 and 200,000 inhabitants. Pamplona (Spain), Geneva (Switzerland) and Harlow (UK), all small-sized cities, lead the HUDI scoring across all categories with scores of 6.8, 6.65 and 6.64, respectively. “The HUDI score differences are often only very small. However, the HUDI shows tendencies and none of the 917 cities achieves a score of 7 or higher out of 10, which gives us an idea of the room for improvement in promoting health and well-being through urban design in Europe," explains Federica Montana, researcher at ISGlobal and lead author of the study.
Large metropolitan cities generally scored better on indicators of urban design (housing density, compactness, mid-rise development and permeability) and sustainable transport (walking and cycling opportunities and number of public transport stops), particularly those in Northern Europe and some in Spain. In contrast, smaller cities show better environmental quality (air pollution, green space and lower urban heat island effects), with higher scores on better air quality and heat mitigation indicators, particularly in Northern Europe.
Differences between Western and Eastern Europe
“One of the trends we observed is that the lowest HUDI scores tended to be concentrated in Eastern European countries such as Romania, Bulgaria and Poland. Conversely, it is in Western European cities, with notable concentrations in the UK, Spain and Sweden that we find the highest scoring cities”, says Natalie Mueller, ISGlobal researcher and co-author of the study.
Not a final ranking
“The HUDI is not intended to be a final ranking of cities, but rather a first approach using only open spatial data to see how European cities of all sizes perform and compare in terms of providing a healthy urban design to their residents”, says Mark Nieuwenhuijsen, director of ISGlobal's Climate, Air Pollution, Nature and Urban Health programme. “Cities of similar size often face similar challenges and opportunities and providing a high spatial resolution of the indicators and combined HUDI scores can help to pinpoint problems and develop targeted intervention strategies. Our HUDI is a work in progress and we invite the research, urban planning and policy communities to develop this work further in the future and make other relevant indicators available”, Nieuwenhuijsen adds.
Top cities by category
The cities with the best HUDI scoring in each category are Madrid (Spain), with a score of 6.04 in large metropolitan cities; Lisbon (Portugal), with a score of 6.09 in metropolitan cities; Bilbao (Spain), with a score of 6.35, in medium-sized cities; Pamplona (Spain), with a score of 6.8, in small-sized cities; and Campobasso (Italy), with a score of 6.02, in the small towns cluster.
Large metropolitan areas (more than 1.5 million inhabitants)
Metropolitan areas (500,000 to 1.5 million inhabitants)
Medium-sized urban areas (200,000 to 500,000 inhabitants)
Small urban areas (50,000 to 200,000 inhabitants)
Small towns (less than 50,000 inhabitants)
Methodology
The Healthy Urban Design Index assesses 917 cities from 26 European countries, including the United Kingdom, and it has been developed using open data sources, including remote sensing data, OpenStreetMap and EU and government open datasets.
The team defined 13 indicators that scientific evidence links to physical and/or mental health and grouped them into four key domains: urban design, sustainable transport, environmental quality and accessibility to green space. For each of the indicators, a reference value was defined based on previous studies or recommendations from experts or international organisations. For example, for the air pollution indicators, the recommendations of the annual average values of particulate matter PM2.5 and nitrogen dioxide (NO2) established by the WHO were used as a reference. For those indicators for which there was no reference value, the value of the city with the best result was used as a reference.
Once the data for all the cities had been obtained for each of the 13 indicators, they were compared with the target value and converted to a score between 0 and 10 depending on the result. The HUDI scores were calculated by applying weights to the 13 indicators and were subsequently used to rank cities within their respective city clusters.
The team hopes to improve the HUDI in the future by including other relevant indicators in the context of urban health, such as socioeconomic indicators, transport modal share, or access to and diversity of services and amenities. “The use of all open source data is an important first step. We are making the codes available and hope that cities can use the evidence to understand the links between urban planning and health. The HUDI helps cities not only see the indicators at the city level but also at high spatial resolution, which is important for equity as there can be large differences across neighbourhoods”, says Carolyn Daher, co-author of the study and coordinator of the ISGlobal Urban Planning, Environment and Health Initiative.
“The HUDI is a useful tool and also a call to action for cities to look at the data and distributions, and use their own data to validate findings, define targeted interventions strategies, and contribute with better data to improve the indicators and mapping in the near future”, concludes Natalie Mueller.
Instructions for accessing the HUDI website
The IDUS pages will be made public once the embargo is completed.
Reference
Federica Montana, Natalie Mueller, Evelise Pereira Barboza, Sasha Khomenko, Tamara Iungman, Marta Cirach, Carolyn Daher, TC Chakraborty, Kees de Hoogh, Alice Battiston, Rossano Schifanella, Mark Nieuwenhuijsen. Building a Healthy Urban Design Index (HUDI): how to promote health and sustainability in European cities. The Lancet Planetary Health, June 2025.
Journal
The Lancet Planetary Health
Article Title
Building a Healthy Urban Design Index (HUDI): how to promote health and sustainability in European cities
Article Publication Date
12-Jun-2025
