Air quality during COVID-19 lockdown and its implication toward sustainable development goals

Air pollution is directly as well as indirectly linked with several of the United Nations Sustainable Development Goals (SDGs). Hence, focused efforts and strategies toward improving the air quality can lead to direct reduction in the adverse impacts on human health and our cities and setting climate mitigation targets. The worldwide outbreak of the novel coronavirus (COVID-19) has forced various governments around the world to suspend nonessential activities due to the unavailability of the vaccine. This unprecedented lockdown led to significant decline in major criteria air pollutants—PM2.5, PM10, CO, and NO2—with more than 50% decline in several cities across the world. However, SO2 did not change much over some regions, while O3 has shown some increase. The majority of these changes are well supported by the reduced pollutant emissions, primarily from vehicular sources in urban areas. A slight decline has also been observed in global greenhouse gas (GHG) emissions during the lockdowns. The lockdown illustrates the need for a potential shift of anthropogenic activities toward a more sustainable lifestyle for ameliorating air quality and thus paving the pathway to achieve SDGs. The COVID-19-induced lockdown scenario should be exploited to understand future measures to improve air quality and mitigate the adverse health and climate effects. This chapter explores the impact of the national lockdowns on urban air quality across the globe. Learnings from this natural intervention and future policy implications toward improving air quality are further discussed.