The negative health effects of air pollution are well known: heart disease, lung cancer, and respiratory diseases such as emphysema. 

Air pollution can also cause long-term damage to people's nerves, brains, kidneys, liver, and other organs. 

Fossil fuel is a hydrocarbon-containing material formed naturally in the earth's crust, and it has been placed under pressure for hundreds of thousands of years. Coal, oil, and natural gas are examples of fossil fuels – and we're using too much of them. 

Some types of air pollution, like smoke from wildfires or ash from volcanoes, occur naturally, but most air pollution is created by people.

A year ago, research from Harvard University revealed that more than 8 million people died in 2018 from fossil fuel pollution.

According to the latest WHO Air Quality Database, over 6000 cities in 117 countries are monitoring air quality, but the people living in them are still breathing unhealthy levels of fine particulate matter and nitrogen dioxide.

Despite the World Health Organization being clear in its advice that policies and investments supporting cleaner transport, energy-efficient homes, power generation, industry, and better municipal waste management would reduce key sources of outdoor air pollution. 

"After surviving a pandemic, it is unacceptable to still have 7 million preventable deaths and countless preventable lost years of good health due to air pollution. That's what we're saying when we look at the mountain of air pollution data, evidence, and solutions available. Yet, too many investments are still being sunk into a polluted environment rather than in clean, healthy air," said Dr. Maria Neira, WHO Director, Department of Environment, Climate Change and Health.