Sustainable Urban Air Quality Management A Review of Policies and Comparative Insights from Global Cities

Air pollution in cities is a tremendous challenge that impacts public health, environmental stability, and the global climate. According to the World Health Organization (WHO), more than 90 percent of the world’s urban population lives in areas where pollutant concentrations exceed recommended limits, resulting in approximately 4.2 million premature deaths annually. The primary objective of this review article is to examine sustainable urban air-quality management strategies and assess their effectiveness using global case studies. Urban air quality problems can be addressed sustainably through technological, regulatory, and behavioral interventions. International policies summarized in this review include low-emission zones (LEZs), congestion pricing, the promotion of electric vehicles, the incorporation of green infrastructure, the use of satellite-based monitoring, and citizen science initiatives. Case studies from major cities such as London, Beijing and Delhi indicate that concentrations of PM2.5, NO₂, SO₂, and O₃ have decreased following specific interventions. For example, the Ultra Low Emission Zone (ULEZ) in London resulted in roadside reductions of PM2.5 and NO₂ by 44% and 35%, respectively. Similar improvements have been reported under Beijing’s Clean Air Action Plan and Delhi’s Odd-Even scheme. The findings of these case studies suggest that integrated, equity-based, and data-driven air quality management models are essential for achieving sustainable urban environmental improvement.