A visual cue for the shift toward cleaner mobility is appearing across European capitals: electric buses, identifiable by charging port icons on their windows, are becoming increasingly common in cities such as Brussels and Madrid. While removing tailpipe emissions from combustion engines is considered by experts to be a straightforward step toward greener transit, a new analysis suggests the journey toward fully sustainable public transport is far from complete.
Michela Le Pira, an assistant professor of transportation at Italy’s University of Catania, noted that eliminating exhaust gases is “the easiest strategy” to improve public transport. However, the broader picture remains challenging. In 2023, nearly 300,000 deaths across the EU were linked to air pollution levels exceeding World Health Organization thresholds, with road transport accounting for approximately 14% of fine particulate matter (PM2.5) in urban areas. Cities alone generate nearly a quarter of the European Union’s transport greenhouse gas (GHG) emissions.
DW, in collaboration with the European Data Journalism Network, evaluated over a decade of data from more than 100 reports to assess sustainability commitments in 33 European cities. The analysis identified 148 pledges from local authorities and operators, focusing exclusively on motorized mass transit.
The EU has set an ambitious goal to become the first climate-neutral continent by 2050, which includes cutting transport-related GHG emissions by 90% compared to 1990 levels. Currently, transportation remains the only major sector where emissions have not fallen below 1990 figures. According to DW’s findings, Copenhagen is the sole EU capital to have nearly electrified its entire bus fleet. In stark contrast, Rome, Lisbon, and Nicosia still rely on diesel for more than 90% of their buses, with metros and trams making up less than 10% of their fleets.
Martin Baierl, a data analyst at the advocacy group Transport & Environment, highlighted that while cars dominate European streets, electric buses offer a viable method for reducing local air pollution. Since 2021, EU funding has accelerated the adoption of electric and alternative-fuel buses. Between 2021 and 2025, the number of electric buses in EU capitals and selected cities rose by 55%, adding 1,234 vehicles to the roads. Electric buses now constitute 20% of the total fleet in these areas, though diesel-only buses still outnumber those running on alternative fuels.
Despite the progress, the transition faces financial and logistical hurdles. Electric buses carry a higher upfront cost than diesel models, and in 20 out of 31 cities with available data, traditional vehicles make up more than half of the bus fleet. Brussels, an early adopter of hybrid technology, is currently moving toward full electrification but at a measured pace. Baierl noted the uncertainty surrounding the optimal long-term technology, pointing to hydrogen-powered buses as another zero-emission option that remains more expensive to operate than electric counterparts.
The data also reveals a gap between ambition and action. DW’s analysis found that only four cities have explicitly committed to achieving zero emissions in their bus or public transport fleets. Meanwhile, public transport usage varies significantly; it accounts for nearly half of trips in Stockholm but only 11% in Ljubljana.
While rail transport is inherently climate-friendly, its availability is limited. Yannis Papadimitriou, a commuter from outside Athens, praised trains as the safest and most environmentally friendly option. However, in many urban areas, buses still outnumber trains and trams, and many of those buses remain diesel-powered.
The environmental impact of public transport extends beyond tailpipes. Indirect emissions from electricity generation and fuel production contribute to the carbon footprint, as do non-exhaust particles from brake and tire wear. Although fine particle emissions from buses have dropped by 92% since 1992 due to stricter standards, non-exhaust emissions from tire wear have risen by 58% over the same period, partly because vehicles have become heavier.
Poul Kattler, a retiree from the Copenhagen area, acknowledged that while the city’s public transport is almost entirely fossil-fuel-free, the construction of new infrastructure carries significant environmental costs. He pointed out that the CO2 balance for new metro lines can be poor during the construction phase, although experts like Le Pira argue that long-term benefits ultimately outweigh these initial emissions.
Experts emphasize that decarbonizing fleets is only part of the solution. Le Pira stated that the primary challenge is shifting the mobility model away from private car use. Private automobiles account for more than a third of transport in the largest EU capitals. Strategies such as discounted fares for students and groups, alongside disincentives for driving like low-emission zones, are being proposed to attract more passengers. Ultimately, Baierl observed that cities where car use is not mandatory are simply more livable.
Electric buses are progress, but what about the hidden emissions from electricity generation? The article hints at this but does not delve deep enough.
Copenhagen leading the charge is great, but where are the other major cities? We need more than just four commitments to zero emissions.
I cannot believe Rome still relies on diesel for over ninety percent of its buses. That is absolutely shocking for a capital city.