Seven billion people, over 95 percent of the world’s population, are breathing air that contains unhealthy levels of pollution, while 60 percent of the world is living in areas that don’t even meet the most basic standards of air quality.

The findings come from the State of Global Air 2018 (PDF), an annual assessment by the Health Effects Institute (HEI) looking at the world’s exposure to air pollution and its health burden using the World Health Organization’s (WHO) Air Quality Guideline.

They found that air pollution contributed to 6.1 million premature deaths worldwide, usually in the form of strokes, heart attacks, lung cancer, and chronic lung disease. That means air pollution is the fourth greatest cause of death, topped only by high blood pressure, poor diet, and smoking.

The problem also seems to be getting worse despite an increasing awareness of the issue at hand. In 2014, just 92 percent of the world's population was living in places where the WHO's recommended air quality levels were not met.

Air pollution is a nasty cocktail of gases and microscopic particles of sulfate, nitrates, ammonia, sodium chloride, black carbon, and mineral dust. The WHO sets guidelines for how many micrograms of fine particulate matter should be found in a cubic meter of air. The vast, vast majority of the world (95 percent) exceeds these guidelines, as you can see on the map below. They then feature three tiers of air quality, where almost two-thirds of the world fit into the poorest quality tier.

As ever, those living in low-income and middle-income countries are the hardest hit.

China and India are particularly choked up. These two countries alone were responsible for over half of the total global pollution-related deaths. India, along with Pakistan and Bangladesh, has seen a steep increase in air pollution over the past decade, however, China is actually winning the war against air pollution thanks to huge investment in green energy infrastructure projects. 

While you might think that air pollution is only a problem for car-filled cities, this report also looked at the much-overlooked damage caused by the burning of wood, charcoal, and animal dung in people’s homes for the first time.

“Air pollution takes a huge personal toll worldwide, making it difficult to breathe for those with respiratory disease, sending the young and old to hospital, missing school and work, and contributing to early death,” said Bob O’Keefe, Vice President of HEI. “The trends we report show real progress in some parts of the world – but serious challenges remain to eliminate this avoidable affliction.”