Climatology and Spatio-Temporal Analysis of Air Pollution Distribution in Megacity of Delhi and Its Surrounding States

Air Quality Index of Delhi dipped overnight on 30 October 2019, climbed upto the dangerous category and red alert alarmed. Now, this has become recurring phenomena every year spanning from last week of October to mid of November. Delhi air quality has radically turned bad to worse with in the span of less than a decade. It raises serious concerns for the air quality of Delhi and demands for the understanding of underlying causes. Analysis of meteorological parameters during the high polluted season revealed that with the onset of winter season, neighboring states of Delhi experiences decrease in wind speed (3.95 m/s) with respect to the normal wind speed prevailing in this area (5–6 m/s). Incidentally, it coincides with the burning of crop plant residue producing an enormous amount of pollutants within short span of time. This leads to accumulation of pollutants due to stagnant atmospheric conditions over Delhi and surrounding states, creating a poisonous environment. This condition aggravates with higher concentration of fire points in Delhi and its surrounding. The study concludes that enhanced pollution conditions in Delhi is mainly due to its land locked status, decrease in synoptic wind, which coincides with increased number of fire events.