Record Rainfall Improves Air Quality Delhi recorded its cleanest air quality of 2024 on Friday, following unprecedented rainfall in September. The city’s Air Quality Index (AQI) dropped to 52, placing it at the upper limit of the “satisfactory” category. Neighboring cities, including Faridabad, Ghaziabad, and Noida, also witnessed significant improvement, with AQIs ranging from 24 to 46, all within the “good” classification.

Delhi Exceeds Annual Rainfall Averages In early September, Delhi surpassed both its annual and seasonal average rainfall, crossing the 1,000 mm mark. The rainfall brought relief to the capital by clearing the air of pollutants. Delhi recorded 54 mm of rainfall at Palam, while the Safdarjung weather station reported 30.9 mm in just three hours on Friday, contributing to this improvement in air quality.

Heavy Rain and Strong Winds Disperse Pollutants The combination of heavy rainfall and strong winds, with speeds of 30-40 kmph, helped disperse residual pollutants, significantly improving the air quality. Delhi’s September rainfall stood at 125.8 mm, which is 55% higher than the normal average, according to official data.

Comparing Rainfall With Previous Years In comparison to September 2023, which saw only 82.7 mm of rainfall—33% below the normal levels—this year’s rainfall is considered “heavy” and has positively impacted air quality throughout the National Capital Region (NCR).

Understanding the AQI Scale The AQI scale ranges from “good” (0-50) to “severe” (401-500). The “satisfactory” category, which Delhi now falls under, is between 51 and 100, indicating that air quality poses little or no risk to the general public.