March 5, 2026: Don’t let the ‘moderate’ AQI fool you. Delhi has an ozone problem

For this episode of Aaj Ka AQI, Newslaundry visited the India Meteorological Department (IMD) on Lodhi Road. While the IMD monitoring system recorded an AQI of 123 at 11 am, our handheld device showed a higher reading of 173 – placing the air quality firmly in the ‘moderate’ category.

According to an analysis by the Centre for Research on Energy and Clean Air (CREA), Delhi just survived its most polluted February in three years. It was also among the warmest Februarys in recent memory, and the two factors are likely intertwined.

Data from the SAMEER app’s AQI calendar shows that ground-level ozone (O₃) was the dominant pollutant for at least 21 days this month. Unlike the protective ozone layer in the stratosphere, ground-level ozone is a harmful secondary pollutant. It forms when nitrogen oxides from vehicles and power plants react with volatile organic compounds (VOCs) – found in fuel vapour and paints – under intense sunlight and heat. 

As the Delhi government aims to resolve the pollution crisis by October 2026, experts warn that tackling “secondary pollutants” like ozone will be just as critical as managing dust and smoke.

Watch.

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