ABSTRACT
In 2019, air pollution was the fourth-largest cause of early death globally. COVID-19 was declared a pandemic in March 2020, resulting in significant economic limitations and drastic changes in human behaviour. Lockdown, social distance, disconnection, and residential isolation are being used to combat the COVID-19 pandemic. However, during the COVID-19 pandemic, an unusually beneficial influence on global air-contamination levels is remarkable. Specifically, experts have predicted a major improvement in air quality and a large reduction in the concentrations of several dangerous gases such as SO2, NO2, CO, and O3. The effects of COVID-19 shutdown on the air quality of the world’s major nations India, China, USA, UK, Australia, Asian countries is considered for the study in this chapter. This chapter focuses on the air quality improvement due to COVID-19 lockdown and positive effects on the environment by using the Air Quality Index (AQI) to represent the pollution level at specific cities for the year 2020 and the previous year 2019 on various harmful gases SO2, NO2, CO, O3, and particulate matters PM2.5 and PM10. This chapter will provide significant information to environmentalists and specialists who will use it to develop future legislation to improve air quality and the environment. Compared to 2019, air quality improved in 67% of worldwide cities in 2020 during COVID-19 lockdown.
