Air pollution in London has plunged since Sadiq Khan became mayor, with a 94% reduction in the number of people living in areas with illegal levels of nitrogen dioxide. The number of schools in such areas has fallen by 97%, from 455 in 2016 to 14 in 2019. Experts described the reductions as dramatic and said they showed the air pollution crisis was not intractable. More than 9,000 people in the capital were dying early each year due to dirty air in 2015. The report from the mayor of London, reviewed by scientists, shows that more than 2 million people in the capital lived with polluted air in 2016, but this fell to 119,000 in 2019. The report, which does not include the further falls in pollution seen after the Covid-19 lockdown began in March, shows levels of nitrogen dioxide (NO2) by roads in central London fell by 44% between early 2017 and early 2020. The pollution cuts have been achieved by charges that have deterred dirty vehicles from entering the city centre and have driven up the use of cleaner vehicles. Putting low-emission buses on the dirtiest routes, ending the licensing of new diesel taxis and extending the amount of protected space for cycling have also contributed. Prof Stephen Holgate, a special adviser on air quality to the Royal College of Physicians, said: "Air pollution is a scourge on society. What the mayor of London has shown in his first term is that major reductions in toxic pollutants can be achieved and that businesses and the public are willing to make the necessary changes to deliver this."