The Clean Air Action Plan in Beijing from 2013 to 2017 successfully reduced emissions of major air pollutants, improving urban air quality. Measures like controlling coal-fired combustion and clean energy transformation led to significant decreases in pollutants like SO2 and PM2.5. Overall, emissions of key pollutants decreased by 39% in 2017 compared to 2013. The plan's focus on adjusting energy and industrial structures played a key role in improving long-term air quality in Beijing.