india

Updated: May 13, 2019 04:37 IST

On Sunday, the pollution levels in the city deteriorated with the AQI (air quality index) recorded at 376 (very poor), according to the air quality monitor at Vikas Sadan near Mini Secretariat.

The early morning voters encountered a partially cloudy sky with dust storm blowing during the mid-morning hours.

While the early and mid-morning hours in the city were relatively cooler, temperatures stayed around 38 degrees Celsius. The mercury rose during the day with the maximum temperature touching 40 degrees Celsius. According to the Indian Meteorological Department(IMD), the weather is all set to improve during the coming week, with temperatures hovering around 38 degrees Celsius with the possibility of rains and thunderstorms.

The Central Pollution Control Board(CPCB) had predicted that there would be a thunderstorm in the city on Sunday that would improve the AQI to moderate (190). As per the CPCB’s AQI bulletin, the AQI stood at 232 on Saturday. However, the pollution levels in the city witnessed a reversal.

Guneet Singh, an air quality expert, attributed the rise in AQI to the low-velocity winds accompanying the dust storm that prevented the pollutant PM2.5 from escaping from the atmosphere. “Showers and thunderstorms would have definitely lowered the AQI readings. The dust and particulate matter in the air get pushed down by water droplets. However, that has not happened. Also, the winds in the dust storm have been of lower velocity. Higher velocity winds often clean up the air especially PM 2.5, which is the primary local pollutant,” he said.

Higher concentrations of PM 2.5 coupled with other pollutants, such as NO2, SO2 and PM 10 deposited in the air by the low-velocity winds in the city added to the pollution levels and imparted a brownish-blue colour to the sky. Residents of the city, who braved the weather to step out for polling, were seen posting updates about the dust storm and the erratic weather.

Namita Gupta, the founder of an air quality monitoring application, said, “The frequency of summer dust storms has increased in the city in the last few years. Coupled with crop-burning activities, these dust storms always lead to an increase in the pollution levels.”