Not all deaths are created equal. In February 2020, the world began to panic about the novel coronavirus, which killed 2714 people that month. This made the news. In the same month, around 800,000 people died from the effects of air pollution. That didn’t. Novelty counts for a lot. At the start of the pandemic, it was considered unseemly to make comparisons like these. But comparing the value of human lives is one thing the machine of modern civilisation does relentlessly, almost invariably to prioritise and absolve the rich – when, for example, the global supply of Covid vaccines is apportioned primarily to the highest-income countries, or when the cost of natural disasters in Bangladesh is measured against the impact of sea-level rise on Miami Beach real estate, or when Joe Biden’s onetime economic adviser Lawrence Summers proposed that Africa, as a whole, was ‘vastly underpolluted’, and suggested that ‘the economic logic behind dumping a whole load of toxic waste in the lowest wage country is impeccable.’

In its first year, the pandemic did damage according to the opposite logic, with the world’s wealthiest countries the worst hit. When people in those countries tried to diminish the threat of the virus by comparing it to the flu, the disease made a joke of them. But air pollution kills more than ten times as many as the flu every single year, and we hear even less about it. In 2017, a Lancet study put the figure at almost seven million a year, about two-thirds from outside air pollution and one-third from indoor, household pollution. More recent estimates run higher, with as many as 8.7 million deaths every year attributable just to the outdoor particulate matter produced from burning fossil fuels. Add on indoor pollution, and you get an annual toll of more than ten million. That’s more than four times the official worldwide death toll from Covid last year. It’s about twenty times as many as the current annual deaths from war, murder and terrorism combined. Put another way, air pollution kills twenty thousand on an average day, more than have died in the aftermath of all the meltdowns in the history of nuclear power: Chernobyl, Three Mile Island, Fukushima and all the others put together. If the pandemic so terrified us that billions of us retreated into panicked cocoons for months, what can explain or justify our blindness and indifference towards the ten million lives ended each year by the repeated inhalation of smog?

Ten million deaths a year is a hundred million a decade. The numbers are so large that even the superlatives of disaster fail. They’re so large that they strain credulity, perhaps partly because none of us can picture someone dying in the street from air pollution and partly because it seems pathetically old-fashioned for a doctor to advise a sojourn in healthier air. But the chances are that you can’t picture a death from obesity or cigarette smoking either, and yet you probably don’t doubt estimates of their toll on human wellbeing, or think it wrong to call Louisiana’s River Parishes ‘Cancer Alley’ – the presence of 150 petrochemical plants has made it an incontrovertibly unhealthy place to live, with some communities registering cancer rates fifty times the national average. Such areas are sometimes known as ‘sacrifice zones’.

A single speck of black carbon, inhaled, won’t stop the heart or poison the lungs, but over time, across populations, the effect is devastating. When we talk about death we always want to see a murderer. When there isn’t one, it’s a lot harder to call it a murder, rather than a tragedy or an act of God. (‘You see one person run over in the street and you’ll never forget it,’ an environmentalist observes in Choked: The Age of Air Pollution and the Fight for a Cleaner Future.* Thousands dying from the effects of dirty air ‘will never even faze you’.) But the central premise of any mortality model is that everyone dies: the question is when, and whether a certain behaviour or environmental factor hastened that end. And while none of these estimates is meant to suggest a single cause of mortality, such as a gunshot wound or a dose of poison in your morning tea, the calculus for air pollution is the same as for obesity or smoking: take the problem away, and the number of premature deaths will fall by many millions. According to new research, half of these deaths, concentrated in the developing world, are the result of consumption and fossil-fuel burning in the world’s richest countries.

The environmental historian Stephen Pyne calls our era the ‘pyrocene’, a global regime of burning: coal and oil, agricultural land and forest, bush and wetland, most of it planned. The Anthropocene, Pyne says, implies dominion over nature. He prefers to emphasise the fact that, wherever you look, the earth is in flames. The residue is carbon monoxide, nitrogen dioxide, ozone, black carbon, sulphur dioxide, and the particularly toxic grouping of small particulate matter known as PM2.5. Everything we burn, we breathe.

Hundreds of millions of people live and breathe in cities permanently clouded by airborne toxic events. In November, the authorities in Delhi closed schools and colleges indefinitely, suspended construction work, and shuttered half of the local coal plants after an episode of ‘toxic smog’ and an order from the Indian Supreme Court to institute emergency measures to combat it. The smog wasn’t new; the response was. Throughout the city, particulate matter hangs around in offices, lobbies and private homes, even those with air purifiers. It often gets so thick that it interferes with air travel. More remarkably, it has interrupted train travel, the smog making it impossible for drivers to see the tracks. Taxi drivers have filtration systems to process the particulates that sneak in. Pedestrians can’t escape it, which is one reason that, on especially smoggy days, living in Delhi is the equivalent of smoking several packets of cigarettes. The city has the highest rates of respiratory illness in the world, and 60 per cent of inhabitants diagnosed with COPD – chronic obstructive pulmonary disease – aren’t even smokers.