Rain, winds give Delhi best July AQI since 2015

CPCB data showed that this July, Delhi logged pollution levels in the “satisfactory” zone on 26 out of 31 days

Consistent rain, coupled with gusty winds, gave Delhi an average monthly Air Quality Index (AQI) reading of 84 — the lowest pollution levels for the month of July since at least 2015, when the Central Pollution Control Board began collecting AQI readings for the Capital, data shared by the CPCB showed.

A clear sky in New Delhi on Monday. (Sanjeev Verma/HT PHOTO)

The average AQI for July this year on par with that of July 2020 — an outlier year due to Covid-19 pandemic-induced restrictions.

CPCB data also showed that this July, Delhi logged pollution levels in the “satisfactory” zone on 26 out of 31 days — better than the 25 “satisfactory” days recorded in 2020 and 2022, and the 20 such days in July 2021.

The lowest AQI recorded so far this year was 59 on July 29. Delhi is yet to record “good” air this year.

CPCB classifies an AQI between 0-50 as “good”, between 51 and 100 as “satisfactory”, between 101 and 200 as “moderate”, between 201 and 300 as “poor”, between 301 and 400 as “very poor”, and over 400 as “severe”.

Analysing the CPCB data, the Commission for Air Quality Management (CAQM) said in a statement, “The monthly average AQI for Delhi in July remained in the satisfactory AQI category (83.71). Delhi has recorded its lowest monthly average AQI during July this year as compared to the corresponding period for the last four years from 2019. The monthly average AQI of July 2023 is comparable with the monthly average AQI of July 2020 (83.80).”

A CAQM official said while the body only looked at a five-year data for July starting 2019, this year was in fact the cleanest since it began recording AQI data. “The years before 2019 were even more polluted,” the official said.

Giving details about the concentration of particulate matter in Delhi this July, CAQM said the city’s average PM2.5 concentration was 35 micrograms per cubic metre (µg/m³) — slightly above the reading of 34µg/m³ in July 2020 and better than the 36µg/m in July 2022.

Meanwhile, the average PM10 concentration for this July was 77µg/m³, the same as 2020 and better than the 82µg/m³ last year.

The national annual safe standard for PM2.5 and PM10 is 40µg/m³ and 60µg/m³, respectively.

CAQM said the improvement in AQI was indicative of the efforts take by commission as well as the state governments across the National Capital Region, asking for the state pollution control bodies, regulatory bodies, industries, RWAs, civil society organizations and citizens to further contribute towards cleaner air.

“CAQM is working closely with various stakeholders concerned to take effective measures for prevention, control and abatement of air pollution and to improve the overall air quality in NCR,” it said.

Anumita Roychowdhury, executive director, research and advocacy at the Centre for Science and Environment (CSE), said while this monsoon season has been marked by prolonged rains in Delhi, long-term trends show there has been a marked improvement in AQI over the years. “We are seeing a drop in annual PM 2.5 and PM 10 levels each year and that is reflecting in the monthly data too. It shows that since 2015, there has been a drop in the background emissions, but we also have to acknowledge the role of meteorological conditions. There has been a washout effect too, largely because we have seen good rain in the last two months,” she said.