Rain effect: Delhi’s July air best in 5 years

New Delhi, July 31

Bountiful rains in July gave Delhi its best air quality for the month in five years, while the average maximum temperature also dropped to its lowest level since 2016, according to official data.

The data from the India Meteorological Department (IMD) and the Central Pollution Control Board (CPCB) also shows that Delhi’s average air quality index (AQI) this year so far is the lowest for the corresponding period since 2019, except for 2020 – the year of the Covid-19 lockdown.

The city recorded 384.6 mm of rainfall in July, which is the second-highest in the month in the last 15 years, compared to the normal of 195.8 mm.

It gauged above-normal rainfall in the last four months — 53.2 mm against a normal of 17.4 mm in March, 20.1 mm against an average of 16.3 mm in April, 111 mm against a normal of 30.7 mm in May and 101.7 mm against a normal of 74.1 mm in June.

The city experienced its highest rainfall (153 mm) in a single day in July since 1982 on July 8-9 due to an interaction of a western disturbance, “monsoonal” winds and cyclonic circulation over northwest India. It received an additional 107 mm of rain in the subsequent 24 hours.

According to CPCB data, the average AQI of Delhi for the January-July period in 2023 was 182.6, showing a significant improvement compared to 209 in 2022, 204.7 in 2021, 159 in 2020, and 215.3 in 2019.

The average AQI in July was the lowest in five years. The AQI for July 2023 was 83.7, while it was 87.3 in 2022, 110.1 in 2021, 83.8 in 2020, and 134.1 in 2019.

On Saturday, Delhi recorded an average AQI of 59, the lowest so far this year.

According to the CPCB data, the daily average PM2.5 concentration in Delhi in July stood at 35 µg/m3, compared to 36 in 2022, 40 in 2021, 34 in 2020, and 47 in 2019. Delhi’s significant improvement in air quality during July was reflected in the fact that all 31 days of the month recorded ‘good to moderate’ air quality.