A Review Study on Air Quality under a Changing Climate: The Dual Role of Greenhouse Gases in Delhi

Delhi, the capital city of India, is among the most polluted urban centers in the world, facing a complex and persistent air quality crisis. This paper explores the dual impact of greenhouse gases (GHGs) in worsening this situation. First, there is the direct role, whereby the primary sources of hazardous airborne pollutants like particulate matter (PM2.5), nitrogen oxides (NOx), and sulfur oxides (SOx) are also the sources of greenhouse gas emissions, such as agricultural practices, industrial operations, and vehicle emissions. The second is the indirect role, in which the formation of greenhouse gases in the atmosphere contributes to climate change, which in turn is causing changes in regional weather trends that intensify Delhi's air pollution. These include variations in wind direction and speed, less winter precipitation, and a rise in the frequency and severity of temperature inversions. This paper examines how these direct and indirect mechanisms interact and emphasizes the need for an integrated approach that tackles both greenhouse gas emissions and air pollution to effectively enhance air quality and protect public health in Delhi.