The Barcelona Institute for Global Health has developed the Healthy Urban Design Index (HUDI) to measure city health and well-being. The results show that smaller cities tend to have better environmental quality. In comparison, larger cities have better urban design and sustainable transport, according to a study published in The Lancet Planetary Health.
The HUDI uses 13 indicators divided into four areas: urban design, sustainable transport, environmental quality, and green space accessibility. It assesses 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 indicator analysed, then calculates an overall HUDI score.
Using this indicator, the team analysed 917 European cities. To compare cities, the team divided them into five categories depending on their number of inhabitants: large metropolitan, medium-sized, small-sized, and small towns.
In general terms, small cities (population between 50,000 and 200,000) have higher overall HUDI scores. The highest scores came from Pamplona (Spain), Geneva (Switzerland), and Harlow (UK), with scores of 6.8, 6.65, and 6.64, respectively. For the largest cities, the highest scores were Madrid (Spain), with a score of 6.04, and Lisbon (Portugal), with a score of 6.09; while Bilbao (Spain), with a score of 6.35, was the highest score in medium-size cities.
“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 scored better on indicators of urban design, such as housing density, compactness, mid-rise development, and permeability, as well as sustainable transport, including opportunities for walking and cycling and the number of public transport stops, particularly those in Northern Europe and some in Spain. In contrast, smaller cities show better environmental quality, including 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.
“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.
“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.”
The data for all cities is publicly available on https://isglobalranking.org/hudi/.
Montana F, Mueller N, Barboza EP, Khomenko S, Iungman T, Cirach M, Daher C, Chakraborty TC, de Hoogh K, Battiston A, Schifanella R, Nieuwenhuijsen M. Building a Healthy Urban Design Index (HUDI): how to promote health and sustainability in European cities. Lancet Planet Health. 2025 Jun;9(6):e511-e526. doi: 10.1016/S2542-5196(25)00109-3