Delhi’s September air quality was moderate for 18 days straight — longest streak since 2016. Here’s why

This September in Delhi has been vastly different from previous years when it comes to weather. For one, the city’s total rainfall — at 136.1 mm — is 10% above the seasonal normal of 123.5 mm. Two, the air quality didn’t spike so much as it stalled — remaining in the ‘moderate’ category — until Tuesday’s rain finally broke the pattern.

Showers and gusty southeasterly winds have offered a reset.

An analysis of Central Pollution Control Board (CPCB) records underscores the growing role of meteorological conditions in governing the Capital’s pollution levels.

What does the data indicate?

For 18 straight days this month, from September 12 to 29, the city’s air quality index (AQI) stayed above 100 without respite. Day after day, residents breathed what CPCB classifies as “moderate” air (AQI