NEW DELHI: Despite light showers on Tuesday, Delhi's air quality reverted to 'very poor' zone, a day after it had improved to 'poor' owing to light rain. Delhi recorded an overall air quality index (AQI) of 305 in the 'very poor' zone on Tuesday, as against 283 in the 'poor' zone, the previous day.
Prior to this, air quality remained in the 'severe' zone for six consecutive days in December - the longest spell of bad air since 2015 (since when air quality records are being maintained in the city).
Delhi-NCR received light showers on Tuesday as well. According to India Meteorological Department (IMD), the Safdarjung Observatory, the base station for Delhi, on Tuesday received 3.6 mm rainfall. The Lodhi Road weather station received 4.4 mm rainfall.
"The showers on Tuesday May show its impact on air quality on Wednesday. However, since this is the last western disturbance affecting the Western Himalayan Region that had its impact on the northern plains, the temperatures will start dropping again from December 30 onwards and air quality is likely to worsen again," said a senior IMD scientist.
He added that the western disturbance that was influencing Delhi-NCR weather till Tuesday, had been keeping the day and night temperatures above normal so far. "From December 30 onwards, minimum temperature is likely to hover around 6-7 degrees Celsius while the maximum temperature may remain around 20 degrees C. With the drop in mercury, the first week of January may see air quality worsening further," he said.
The union ministry's early warning system of weather and air quality forecasting said that while light showers on Monday helped improve air quality from 'severe' to 'poor', but Tuesday's showers are likely to have an impact on Wednesday, which may improve air quality to 'lower end of poor' or 'moderate' zone.
It also warned, "On December 30, 31 and January 1 winds are likely to be low reducing ventilation of pollutants and AQI is expected to be within 'poor' category. From January 2 onwards improvement in AQI is likely due to relatively high winds."
Delhi’s air quality this December has mostly been in the 'very poor' zone with six consecutive 'severe' air quality days. This month so far has only seen seven days in the 'poor' category.