Wind gifts Delhi cleanest November air since 2020

Delhi clocked an air quality index (AQI) of 260 on Wednesday, according to the Central Pollution Control Board’s (CPCB) 4pm bulletin (taken as the reading for a city’s pollution levels), a sharp dip from 372 on Tuesday.

Residents of Delhi on Wednesday woke up to the unlikely November sight of a clear sky and a city free of the grey haze that has shrouded it for several days, as overnight winds from the southeast gave the Capital its cleanest air since late October.

The concentration of pollutants in the Capital on Tuesday was also at its lowest since a reading of 259 on October 23 this year. (Rahul Singh)

Delhi clocked an air quality index (AQI) of 260 on Wednesday, according to the Central Pollution Control Board’s (CPCB) 4pm bulletin (taken as the reading for a city’s pollution levels), a sharp dip from 372 on Tuesday.

Wednesday was the city’s cleanest day in November since 2020, showed CPCB data. That year, Delhi recorded an AQI of 231 on November 29.

The concentration of pollutants in the Capital on Tuesday was also at its lowest since a reading of 259 on October 23 this year.

Pollution levels in the city continued to fall all day, with the air quality turning late Tuesday itself, as the AQI improved after 11pm. At 10am on Wednesday, Delhi logged an AQI of 309, which improved consistently till 226 till 9pm.

An AQI between 201 and 300 is classified “poor”, and one from 301 to 400 is “very poor”.

Meanwhile, there was a dip in farm fires in Punjab, which largely fuel the Capital’s November pollution crisis.

The state recorded 1,778 farm fires on Wednesday, up from 608 on Tuesday, but lower than 2,487 the day before that, and well below the peak of 3,634, detected on November 2. Punjab agriculture director Gurwinder Singh said that 92% of the area under paddy cultivation in the state has been cleared, and the rest will be removed by the end of the week.

Punjab, Haryana and Uttar Pradesh recorded a combined count of 1,905 fires on Wednesday, contributing to 5% of Delhi’s PM2.5 concentration.

Rajasthan and Haryana got rain on Wednesday, said officials of the India Meteorological Department (IMD), with Delhi enjoying the knock-on benefits of the spells.

“Wind speeds went as high as 18 km/hr in the early hours of Wednesday, allowing Delhi to wake up to a relatively clean day as pollutants had dispersed,” said VK Soni, scientist at IMD.

Soni said that though winds will blow in from the northwest by Thursday, local gusts will negate the impact of stubble emissions.

Forecasts by the Early Warning System (EWS) show that the AQI is likely to be “poor” till Saturday.

The minimum temperature in Delhi on Wednesday, 16.9 degrees Celsius, was three degrees above normal, but Met officials said nights will get cooler over the week.

“This will be due to a western disturbance, which has brought snowfall to parts of the Himalayas,” said RK Jenamani, scientist at IMD.