People weren't commuting to the office or going to restaurants and gyms, so there were fewer cars on the road [0]. Fewer of [anything that exudes toxins] will

People weren't commuting to the office or going to restaurants and gyms, so there were fewer cars on the road [0]. Fewer of [anything that exudes toxins] will result in increased air quality; cars, factories, even humans to an extent. Now that more people are going back to the office, restaurants, and/or gyms, the air quality has "increased" back to the level it once was. [1] [0] https://www.scientificamerican.com/article/the-pandemic-showed-the-promise-of-cities-with-fewer-cars/ https://www.scientificamerican.com/article/the-pandemic-show... [1] https://www.esa.int/Applications/Observing_the_Earth/Copernicus/Sentinel-5P/Air_pollution_returning_to_pre-COVID_levels https://www.esa.int/Applications/Observing_the_Earth/Coperni...