Pollution was responsible for nine million deaths worldwide in 2019, experts said.

Air, chemical and water pollution accounted for one in six deaths worldwide, with little progress on tackling the public health crisis in four years, a new study found.

The findings, an update to the Lancet Commission on Pollution and Health, showed that despite declines in some risks, pollution still led to nine million early deaths in 2019 – a figure unchanged since 2015.

Pollution is the world’s largest environmental risk factor for disease and premature death, the report published in the Lancet Planetary Health warned.

The number of deaths linked to pollution associated with extreme poverty such as unclean water, a lack of sanitation and household air pollution from burning fuels such as wood for cooking and heating have fallen.

But this was offset by increases in deaths attributable to outdoor air pollution and toxic chemicals such as lead poisoning.

Air pollution – both indoor and outdoor – causes more than 6.6 million early deaths globally, with the number increasing, while lead and other chemicals are responsible for 1.8 million death a year, the researchers said.

Over the past two decades, deaths caused by modern forms of pollution such as dirty air from burning fossil fuels and toxic chemicals have increased 66% in the face of increased industrialisation, uncontrolled city development, population growth and a lack of regulation.

Pollution remains a major global threat to health and prosperity, and international action on all major pollutants is needed, the report said.

More than 90% of pollution-related deaths occur in low-income and middle-income countries, and most countries have done little to deal with the “enormous” public health problem, it warned.

Pollution, climate change and wildlife loss are closely linked, and action to tackle one could help deal with the other crises.

A large-scale, rapid shift away from all fossil fuels, which give out pollutants such as particulate matter and nitrogen oxides as well as carbon emissions when burned for energy in vehicles, boilers or power plants, would help tackle air pollution as well as slow down climate change.

Richard Fuller, lead author of the study, said: “The health impacts of pollution remain enormous, and low- and middle-income countries bear the brunt of this burden.

“Despite its enormous health, social and economic impacts, pollution prevention is largely overlooked in the international development agenda.

“Attention and funding has only minimally increased since 2015, despite well-documented increases in public concern about pollution and its health effects.”

Co-author Professor Philip Landrigan, director of the Global Public Health Programme and Global Pollution Observatory at Boston College in the US, said: “Pollution is still the largest existential threat to human and planetary health and jeopardises the sustainability of modern societies.

“Preventing pollution can also slow climate change – achieving a double benefit for planetary health – and our report calls for a massive, rapid transition away from all fossil fuels to clean, renewable energy.”