Air pollution has been one of the most severe forms of environmental damage. Figures from the World Health Organization estimate that air pollution kills 7 million people worldwide every year. Its data also shows that 9 out of 10 people in the world breathe air that exceeds WHO guideline limits on high levels of pollutants. According to International Energy Agency, average activity on the world's roads fell by almost 50% compared with 2019.The improvement in the air quality was clear to see.