Life is powered by the breath. The lungs supply us with oxygen and put it into the blood, which carries it to the organs that allow us to walk, talk and move. To live.

But even though we all breathe, we don't all breathe the same air. Air is about 78% nitrogen, 21% oxygen, and small amounts of other gases, including carbon dioxide, helium, and hydrogen. It is also composed of a number of pollutants. Polluted air can damage every organ and cell in our body.

It contributes to the onset of diseases ranging from heart and lung diseases to diabetes and dementia, from cancer to bone fragility, from skin lesions to asthma. The World Health Organization has labeled air pollution a public health emergency, given that 99% of the world's population breathes toxic air. The nine million early deaths caused by air pollution each year make it deadlier than smoking. These deaths disproportionately affect the most disadvantaged in society: more than 90% of deaths related to air pollution occur in low- and middle-income countries, where laws are ineffective or are not respected, vehicle emission standards are less stringent and the burning of fossil fuels is more widespread.

The main causes of bad air quality are also the causes of the climate crisis. Air pollution and global warming have largely the same culprits: greenhouse gases, especially those produced by transport, industry and energy generation. Energy production (the main source of greenhouse gas emissions) causes 85% of particulate air pollution and almost 100% of nitrogen oxide emissions. This means that the solutions to air pollution and climate change are often the same. If you face one of the two problems, you face both.

Climate change and air pollution are mostly invisible killers. Citizens cannot see them. And that means politicians can ignore them. Although governments around the world love to set goals, often the laws to achieve them never arrive.

London was one of the first cities in the world to declare a climate emergency. He introduced the world's first Ultra Low Emission Zone (ULEZ) – an area where drivers of the most polluting vehicles must pay a fee – which nearly halved toxic air pollution in central London.

Since the election of the new Mayor in 2016 London has seen a 94% reduction in the number of people living in areas with illegal levels of nitrogen dioxide. Not to mention the 440,000 trees that have been planted, the five-fold cycle lanes, the record number of electric charging points installed and the largest zero-emission bus fleet in Europe. These changes were not forced upon Londoners. It was the citizens of London who voted for them. Today the four million Londoners who live in the expanded Ulez area are breathing cleaner air.

It is the story of the personal transformation of the Mayor of London: from Land Rover driver to electric bike evangelist. It's the story of working with experts, Londoners and mayors from around the world to tackle an issue that affects us all. But above all it is the story of an awareness, because he understood that climate change is not the kryptonite of politics. The fight for decisive climate action is a fight that engaged citizens, activists and politicians can win.

This is the story of Mayor SADIQ KHAN who has spoken to countless people in recent years (voters and activists, politicians and fellow mayors from all over the world) who said they had to face the same problems to fight the battle on climate change. All of these people cite the problem of apathy: the daunting task of getting citizens (voters) to care about the environment when their lives are overwhelmed by more pressing issues.

Source SADIQ KHAN Mayor of London