MagicBones/ShutterstockSeventy years ago, London choked. For five days in December 1952, a toxic smog smothered the city. Visibility collapsed. Transport failed. Thousands died. It was not a natural disaster. It was the product of policy failure.Out of that catastrophe came one of the most important environmental laws in UK history: the Clean Air Act 1956. It was a turning point. It showed that science, when taken seriously, can transform public health.But the story does not end in 1956. Because the same forces that delayed action then continue to shape air pollution policy today.The Clean Air Act was born from evidence. The Beaver committee’s 1954 report, named after its distinguished chairman, Sir Hugh Beaver, made a simple but powerful case: air pollution was not inevitable. It was a social and economic problem that could be solved.The law followed. Smoke-control areas were introduced. Dirtier fuels were phased out. Emissions were regulated. Over time, air quality improved dramatically.This model spread globally. Evidence-led regulation became the foundation of air pollution control in many countries such as the US, Japan, Germany and Australia. Monitoring improved. Health effects became measurable. Courts began to hold governments accountable. Read more: These colourful diagrams show how air quality has changed in over 100 countries around the world since 1850 Major global successes followed this template. The Montreal protocol, a landmark treaty agreed in 1987 after the discovery of the ozone hole, showed how fast action based on strong science could prevent a planetary crisis. When science leads, lives are saved.But the 1956 Clean Air Act was not passed easily. Industry resisted. Industrial interests feared the cost of cleaner technologies. Political leaders hesitated.Historical analysis shows that senior figures, including the government’s housing minister, Harold Macmillan, emphasised economic concerns and downplayed the risks of smoke and sulphur pollution during the early 1950s.The science was already clear. The political response was not. It took pressure from outside government to break the deadlock. Public health advocates, local politicians and media campaigns all contributed. Only then did policy shift.This pattern is one that continues today.Even after 1956, action often came slowly. Leaded petrol remained in use in the UK until 2000, despite decades of evidence on neurotoxicity. Acid rain warnings were initially dismissed before international cooperation emerged. Air quality standards improved gradually, often only after legal or public pressure to cut pollution.The lesson is uncomfortable. Science alone does not drive policy. Power does.The modern eraToday’s air pollution looks different. It is less visible. More chemical. More complex. But it remains deadly. According to the Royal College of Physicians, around 40,000 people die every year in the UK due to air pollution. Globally, the burden is far greater. An estimated 5 million deaths are linked directly to fossil fuel air pollution annually.The sources are modern. Traffic emissions. Domestic heating. Agriculture. Industry. But the core issue remains unchanged. Pollution follows the money.A growing body of evidence suggests that fossil fuel interests continue to shape political decision-making across multiple political systems. In the UK, investigative analyses indicate that the Conservative party has received substantial funding from fossil fuel-linked donors, while networks of industry-aligned thinktanks and lobbying groups have influenced policy direction. Similar patterns have been identified in Reform UK, whose funding base has been heavily concentrated among fossil fuel interests.The trend is global. In the US, the Republican party and the campaigns of Donald Trump have received extensive support from the fossil fuel sector, alongside significant lobbying expenditure designed to shape policy outcomes.These networks do not just fund politics. They shape it. Evidence suggests they have contributed to subsidies to the fossil fuel industry alongside delays and reversals in climate and air-quality policies, including the weakening of emissions targets and support for new fossil fuel extraction. An ultra-low emission zones was introduced in London’s city centre in 2019. Alena Veasey/Shutterstock Scientific consensus is clear. Burning fossil fuels drives both climate change and air pollution. Reducing emissions delivers immediate health benefits.Yet policy decisions often move in the opposite direction. Expanding oil and gas extraction. Delaying the transition away from petrol and diesel vehicles. Weakening environmental regulations. These choices directly conflict with the evidence. They also follow a pattern familiar from the 1950s. Economic arguments are used to justify delay. Uncertainty is emphasised. Long-term health costs are discounted.The difference today is scale. Air pollution is no longer just a local issue. It is global.The health burden of air pollution is vast. In the UK alone, tens of thousands of premature deaths are linked to exposure to fine particulate matter known as PM2.5 – tiny particles 2.5 micrometres or smaller that can penetrate deep into the lungs and bloodstream – each year. These people have heart disease, stroke, respiratory illness and their life expectancy is reduced. The health effects are far from equal. Pollution exposure is higher in deprived communities. Health consequences are unevenly distributed.Seventy years after the Clean Air Act, the lessons are clear. Disasters should not be required to trigger action. The Great Smog forced change. But policy should anticipate risk, not respond to tragedy.We are now at another turning point. Air pollution remains one of the leading environmental causes of death worldwide. At the same time, the tools to reduce it have never been more available. Clean energy. Cleaner transport. Better regulation. Stronger data. Policy just needs to follow the science.Ian Williams receives funding from UK Research Councils, including the Engineering and Physical Sciences Research Council (EPSRC) and its Impact Acceleration Account.