What Three Decades of Advancing Clean Air Taught Us—and Where We Go from Here

In 1990, facing a public health crisis, Mexico City initiated its first multiyear air quality management strategy, significantly reducing lead and sulfur emissions. These results were driven by a regional-focused approach, key regulatory reforms, and investments in data monitoring – all geared toward ensuring sustained and measurable impact.

That is what the Knowledge Bank is about—connecting evidence, operational experience, financing, and partnerships to deliver solutions that create jobs and drive impact at scale.

World Bank Group (WBG) research finds that outdoor air pollution kills roughly 5.7 million people globally each year. Its economic costs are estimated at nearly 5 percent of global GDP, due to its impacts on health, productivity, and life expectancy. Cleaning the air and building lasting economic growth are not competing goals. They are the same investment, leading to more productive societies, more competitive companies, better jobs, and healthier families.

The WBG has been working to support air quality management (AQM) in and across countries for several decades—starting in the 1990s by addressing air pollution from targeted sources such as transport in Mexico City and coal-fired boilers in Beijing.  Our investment portfolio was unlocked by the steady, methodical buildup of evidence that showed how air pollution was a measurable and large drag on development, and by the production and curation of knowledge around how to engineer solutions across sectors. None of this would have been possible without the ability to mobilize trust fund resources—from the Trust Fund for Environmentally and Socially Sustainable Development (TFESSD), the Bank-Korea Environmental Partnership (BKEP), and the Pollution Management and Environmental Health (PMEH) Trust Fund.

From this experience, we’ve distilled four key lessons:

1.      Building the evidence base matters. While we’ve worked on air quality since the early 1990s, the initial focus was largely on physical investments at the local level with limited development policy conversations. Governments couldn’t quantify what dirty air was costing them in lives, hospital beds, or lost workdays. Nor did they have the data and analytical tools to pinpoint what was causing the air to turn bad. As a result, governments couldn’t justify the comprehensive and targeted reforms that cleaning it up would demand. We built that evidence: mapping pollution sources, quantifying health and economic impacts, and developing tools to show which interventions would deliver the most benefits in a cost-effective way.

2.      Solutions must be time-bound, measurable, and cross-cutting. Repeatedly, we found that governments were working from a narrow set of interventions with no systematic way to model what meeting their air quality standards would require. Working alongside national and international research institutions, we helped engineer a shift to programs with clear, time-bound targets spanning sectors like energy, industry, transport, agriculture, and waste. PM2.5 levels in the Greater Beijing region have fallen sharply. In Greater Cairo, World Bank Group-supported policy interventions cut waste burning incidents by nearly two-thirds in a single year, and particle matter (PM10) fell to its lowest level ever recorded, dropping by more than 30 percent between 2020 and 2025.

3.      Local champions help knowledge live. Working alongside national institutions in Mexico, Chile, Egypt, China, Mongolia, and India was key to adapt tools to local data and navigate the reality of local concerns. This meant that global knowledge was applied and translated rather than simply transplanted. This created ownership of both the problem and the solutions.  

4.      Awareness matters as much as analysis. Getting the science right matters. But so does getting the message across. In Mexico, the ProAire Program supported environmental education, public awareness campaigns and citizen participation in AQM interventions to create a sustainability culture. In China, multi-year broadcasting programs we helped develop wove environmental evidence into artistic storytelling, helping turn air quality into a public issue that gained traction in policy discussions. Similar approaches were deployed in Mongolia and are now being developed in Egypt and India, tapping sports stars to deliver messages directly to their fans.

Where this goes next

The burden of air pollution falls hardest on the countries least equipped to carry it. Sub-Saharan Africa and South Asia experience some of the world’s worst air quality while facing under-resourced health systems and limited fiscal space. Yet in these places, investing in clean air is, in effect, investing in public health, labor productivity, and economic growth. The case for action is clear. The financing is harder.

Public budgets alone will not close that gap. Instruments such as blended finance, guarantees, outcome bonds can help bring private capital into exactly the sectors that dirty the air: cooking, heavy industry, transport, waste management. But deploying them at speed and scale requires partners around the table from the start. For example, the Regional Science, Policy and Finance Dialogue for AQM in the Indo-Gangetic Plains and Himalayan Foothills has laid the foundation for regional AQM, bringing together key South Asian countries since 2022 to showcase best practices and share knowledge—helping catalyze our US$1.25 billion clean air portfolio across Bangladesh, India, Nepal, and Pakistan.

Decades of this work has taught us that you cannot rush the foundations. But once they are in place, you can move faster and further than expected. That is the challenge development finance must meet. Clean air is an economic, health, and development imperative—and delivering it requires long-term investment, strong institutions, and partnerships that can sustain action over time.

Source : World Bank