Delhi Air Quality Index falls: October is here! Check factors behind Delhi’s rising Air Pollution

Delhi Air Quality, Air Pollution level: The month of October brings menace of air pollution to Delhi. Like previous years, this year too, Air Quality in the national capital started witnessing a major drop. While the stubble burning remains one of the reasons, there are several other factors that deteriorate the air quality and result in rising air pollution levels.

Wind direction: During the monsoon season, the wind direction remains easterly. With October marking the withdrawal of the monsoon, the wind direction changes and become northwesterly. National Physical Laboratory scientists revealed that only 28 per cent of Delhi’s winds come from the Indo-Gangetic plains as 72 per cent comes from the northwest. The dust that these northwesterly winds carry often dilutes the air quality in Delhi.

Temperature: As temperatures in Delhi start to dip, levels increase. The dipping temperature leads to a lowering of the inversion height. When this happens, the concentration of pollutant levels in the air. Inversion height is the layer beyond which pollutants fail to disperse into the atmosphere’s upper layer.

Wind-speed: Along with the temperature, wind speed dips during winters. High-speed winds play a pivotal role in dispersing pollutants

Stubble-burning, farm fires: Stubble-burning or farm-fires has been the most highlighting point behind the Delhi pollution. In 2015, an IIT-Kanpur study revealed that 17 per cent to 26 per cent of all particulate matter in the national capital during the winters is due to the biomass burning. In 2019, the contribution of stubble burning reached 40 per cent. In the last few days, stubble-burning’s contribution has remained between 2 percent and 4 percent. However, as November comes closer, this figure will go up.

Dust and vehicular pollution are considered as the two biggest causes of air pollution in the national capital.