The UK has one of the worst records of pollution death of any country in Europe, a major study has found.
Around 50,000 deaths last year in the UK can be attributed to toxic air and man-made chemicals, according to the investigation by researchers in New York.
Globally, pollution claimed nine million lives in that one year - one in six of all deaths, said researchers.
Air pollution from vehicles and factories was the biggest killer, accounting for 6.5 million deaths on its own.
In the UK, 8.39% of deaths were due to pollution, a higher proportion than in many other European countries including Germany, France, Spain, Italy, Denmark, Sweden and Switzerland.
More than 155,000 people were killed by pollution in the US, but those deaths made up just 5.74 per cent of the country's total.
Most pollution victims around the world died as a result of non-communicable conditions such as heart disease, stroke, lung cancer and chronic obstructive pulmonary disease (COPD), said researchers.
Worldwide, the biggest impact from pollution was felt in regions undergoing rapid development and industrialisation.
In an effort to tackle the rising death toll attributable to pollution in London, Sadiq Khan is introducing the T-charge from next week.
It is a £10 surcharge applied to the most polluting vehicles driving in central London.
From 23 October, cars, vans, minibuses, buses, coaches and heavy goods vehicles in central London will need to meet minimum exhaust emission standards or pay the fee in addition to the congestion charge.
Toxic air is blamed for an annual death toll of about 9,000 in the capital alone.
Jonathan Bartley, co-leader of the Green Party, warned pollution "is fast becoming one of the most urgent global crises of our times".
"The toll is three times higher than deaths from AIDS, TB and Malaria combined," he said. "If we do not take drastic action now millions more will die prematurely.
“Britain is falling woefully behind other countries when it comes to cleaning up our air, with the Government’s plans to tackle the crisis so bad they have been found illegal. This is shameful. We must learn from cities like Paris taking bold measures to cut pollution."
In the most severely affected countries, including India, Pakistan, China, Bangladesh, Madagascar, and Kenya, up to a quarter of all deaths were caused by pollution.
Around 2.5 million people in India were killed by pollution in 2015 - nearly a quarter of all deaths - and 1.8 million in China.
Professor Philip Landrigan, from the Icahn School of Medicine in New York City, US, who co-led the investigation, said: "Pollution is much more than an environmental challenge - it is a profound and pervasive threat that affects many aspects of human health and well-being.
"It deserves the full attention of international leaders, civil society, health professionals, and people around the world.
Despite its far-reaching effects on health, the economy and the environment, pollution has been neglected in the international assistance and the global health agendas, and some control strategies have been deeply underfunded.
"Our goal is to raise global awareness of the importance of pollution, and mobilise the political will needed to tackle it, by providing the most in-depth estimates of pollution and health available."
The Lancet Commission on Pollution and Health was a two-year project involving more than 40 international researchers looking at a snapshot of pollution effects around the world in 2015.
Scientists analysed data from the Global Burden of Disease study, a huge inquiry into the leading causes of death and illness worldwide, to come up with the findings published in The Lancet journal.
The biggest cause of pollution death was found to be chemicals in the air, both outside and within households.
Outdoor pollution was chiefly caused by road traffic and industrial emissions while indoor air pollution resulted from the burning of wood, charcoal, dung and crop wastes.
After air pollution, the greatest hazard was contamination of water supplies and sanitation, leading to infectious disease. Unsafe water was linked to 1.8 million deaths.
Toxic chemicals and carcinogens in the workplace accounted for 800,000 deaths from conditions such as cancer and lung disease.
Pollution was found to impose a massive economic burden in some parts of the world, equivalent to 1.3% of Gross Domestic Product in low-income countries.
Pollution-related disease soaked up an estimated 1.7% of healthcare spending in high-income countries such as the UK and 7% in middle-income countries.
Commission author Karti Sandilya, from the non-profit organisation Pure Earth USA, said: "Pollution, poverty, poor health, and social injustice are deeply intertwined. Pollution and related diseases most often affect the world's poor and powerless, and victims are often the vulnerable and the voiceless."
Among all the western European countries included in the study, only Belgium had a worse record than the UK in terms of the proportion of deaths blamed on pollution - 8.59%.
Estonia (7.22%) and Slovenia (7.94%) both had a better record than the UK. Proportional levels of pollution death were greater in Russia (8.57%), Poland (10.8%), Hungary (9.72%), Slovakia (8.95%) and the Czech Republic (8.47%).
Dr Penny Woods, chief executive of the British Lung Foundation, said: "This report reveals the consequences air pollution can have when left unchecked.
"Air pollution is reaching crisis point worldwide, and the UK is faring worse than many countries in Western Europe and the US.
"A contributing factor could be our dependence on diesel vehicles, notorious for pumping out a higher amount of poisonous particles and gases.
"These hit hardest people with a lung condition, children and the elderly."
Simon Gillespie, chief executive of the British Heart Foundation, added: "In the UK, poor air quality disproportionately affects some of the most disadvantaged and vulnerable members of our communities, including the young, elderly and those with existing cardiovascular conditions.
"It's time for change."
A Defra spokesman said: "We have put in place a £3 billion plan to improve air quality and reduce harmful emissions.
"We will also end the sale of new diesel and petrol cars by 2040, and next year we will publish a comprehensive Clean Air Strategy which will set out further steps to tackle air pollution."