The following is a public statement by C40 Co-Chairs, Mayor of London and the Mayor of Freetown, at the WHO Conference on Air Quality in Cartagena, Colombia:
Your Excellencies, distinguished delegates, esteemed colleagues,
As Mayors of London and Freetown, and co-chairs of C40 Cities, we represent the world’s largest cities on the front lines of the air pollution and climate crisis. C40 Cities is a network of nearly 100 world-leading cities, working together to take urgent action on the climate emergency and improve air quality for over 650 million people. As mayors of some of the world’s largest cities, we are committed to addressing the air pollution crisis that claims over 8 million lives annually and disproportionately affects the most vulnerable in our societies.
We welcome the World Health Organization’s updated road map to address the health impacts of air pollution, which sets an ambitious goal of reducing the population-attributable fraction of deaths from air pollution by 50% by 2040, relative to 2015. Achieving these ambitious targets will save millions of lives lost to the devastating harm of pollution, improve public health, reduce the avoidable burden on healthcare, and make our cities more liveable for communities to thrive.
Our cities are showing that evidence-based action can deliver tangible results. Through commitments 50 cities have made in C40’s Clean Air Accelerator we have set ambitious clean air targets, we are implementing bold new policies and programmes, and we are transparently reporting on our progress each year since 2019. Our most recent progress report published just last month, highlighted that cities around the world are prioritising clean air policies and programmes that are cleaning the air for millions of people. These actions include expanding zero-emission transport systems, establishing clean air zones, implementing clean energy solutions for heating, supporting active and sustainable mobility and improving waste management, and many others.
But our efforts don’t stop here. Through our flagship air quality initiative, Breathe Cities, together with our partners – C40, Clean Air Fund and Bloomberg Philanthropies, we are working with 14 cities worldwide to drive clean air action from Bangkok to Johannesburg, and from Rio to Nairobi. Together, we aim to reduce air pollution and planet-warming emissions by 30% across participating cities by 2030.
Cities across the world are already leading the way:
- London’s Clean Air Zone has reduced roadside NO2 by over half in central London and by nearly a quarter in outer London. All Londoners are now breathing cleaner air, with more deprived communities seeing even greater benefits.
- Warsaw cut PM2.5 levels by 33% between 2017-2023 through cleaner heating policies and financial support for residents.
- Bogotá is deploying a new 100% electric bus fleet, improving air quality for 35,000+ residents while promoting gender inclusion in transit jobs.
- Jakarta doubled its public transit network in five years while cutting commuter costs from 30% to 10% of average income.
- Barcelona improved air quality near 200+ schools through urban design and street-calming measures. The city has achieved the cleanest air since records started and reduced 32% of health impacts from pollution between 2020 and 2023.
- Addis Ababa built 96 km of pedestrian walkways and 100 km of bike lanes to promote active transport.
- Berlin expanded its cycling network by 88 km between 2021-2023, aiming to reduce car traffic by 18% by 2030. Over the past five years, emissions at street-level monitoring stations have fallen by more than 25% for NO2 and by around 17% for PM2.5 in Berlin.
- Accra and Amman are integrating informal waste workers into formal recycling programmes, improving air quality and creating green jobs.
- Seoul’s PM2.5 concentration had dropped 23% relative to 2016 through implementation of measures in the “Seoul Air Quality Management Implementation Plan (2020–2024)”.
- Paris has reduced the number of residents exposed to high levels of NO2 from 250,000 in 2019 to just 2,500 in 2023 due to a range of local and regional measures to address transport emissions.
Breathing clean air is not a luxury—it’s a fundamental human right that should be accessible to everyone, everywhere. We recognise that air pollution is not just an environmental crisis—it is a public health emergency and a matter of justice. Communities from lower socio-economic backgrounds often disproportionately represented by racial or ethnically marginalised groups, children, women, older adults, outdoor workers, and those living with disabilities or chronic diseases, bear the brunt of toxic air, leading to severe health disparities, major burdens on their quality of life and on public health systems. By prioritising clean air policies that protect those most at risk, we can create healthier, fairer, and more livable cities for all.
However, our cities cannot do this alone. We urge governments at all levels, including national, regional, and local levels, to take urgent action. In particular, we call on the national governments convened by the World Health Organization this week to prioritise the following actions:
- Scaling up financial support and incentives: Significantly expand investments in clean air solutions, including zero-emission public transport, renewable energy deployment, and cleaner industrial processes. National funding must prioritize cities, where pollution is most concentrated and action can have the greatest impact. Additionally, governments should establish targeted subsidies to help low-income communities transition to clean energy and sustainable mobility, ensuring that air quality improvements benefit everyone equitably.
- Strengthening air quality monitoring and transparency: Expand and modernise air quality monitoring networks to ensure comprehensive, real-time data collection. Reliable data is critical for governments at all levels to track pollutant concentrations, assess health risks, and design evidence-based policies.
- Expand city-national collaboration: Establish mechanisms to integrate cities into national air quality planning and policymaking and support regional coordination for effective air quality management. National governments must recognise cities as key partners in developing and implementing clean air strategies.
We also welcome the vital role of the health sector at the heart of the economic case for action and investment in clean air. The benefits of clean air will be felt first and foremost by patients, and in savings to health authorities. We are committed to working closely with the health sector to advocate for stronger policies and ensure that air pollution is recognised as a public health emergency requiring urgent intervention.
Through the C40 Clean Air Accelerator and the Breathe Cities initiative we will continue to work to align city-led commitments and action inline with the WHO Air Quality Guidelines and the ambition set out in the WHO’s Global Road Map for Air Quality, and we urge other cities to join us in this commitment.
Cities around the world are ready to step up and intensify our efforts to tackle air pollution and we invite more to join us. As the first responders to our residents’ needs, we are committed to this fight, working closely with our partners in national governments and global institutions to build healthier, fairer, and more livable cities for all.
Clean air is not a privilege, it is a fundamental right. Together, we can turn this vision into reality.
Thank you.