Air at 8 out of 10 hot spots in Delhi hasn’t improved much in 5 years: Data
Delhi's pollution hotspots show minimal air quality improvement since 2019, with PM2.5 levels remaining high and inconsistent across monitoring stations.
The air quality at Delhi’s pollution “hot spots” from 2019 has not significantly improved over the past five years, especially when compared to how the rest of the city has fared in the same period, an analysis by HT revealed.
To assess whether air quality has improved at hot spots relatively more than the rest of the city, HT checked PM2.5 concentration levels from 33 monitoring stations between October 1 and November 10 (six stations were excluded because they had data for less than 90% of days in at least one year from 2019 to 2024). The analysis showed that while pollution levels have declined in 2024 at these hot spot stations when compared to 2019, these improvements are less substantial than the city’s overall average reduction in PM2.5.
Among the 10 most polluted stations in 2019, eight have shown less improvement than the average, suggesting no substantial progress at these hot spots.
To be sure, the simple answer to this question is somewhat meaningless because the weather (which has a big influence on air quality in the city) is not the same every year.
However, one can say that government action is checking pollution at hotspots if the change in air quality there is more favourable than the city on average. On this metric, pollution hotspots have not seen any significant change in the past five years, the HT analysis showed.
The analysis also points out that this year’s apparent improvement over the base period may be partly due to weather conditions – with higher-than-normal October and November temperatures and faster winds dispersing pollutants active this year.
The minimum and maximum temperatures in October and November have largely trended higher than normal in Delhi, which prevents pollutants from accumulating near the surface. Moreover, the large mass of pollutants that was pumped into the air on Diwali was quickly cleaned by faster winds on the following days.
Thus, the slight reduction in pollution levels may not represent a sustainable improvement in air quality.
Moreover, while PM2.5 levels at these hot spots have dropped, they remain in a high AQI range, similar to 2019 levels.
In 2019, all the 10 stations averaged a PM2.5 concentration that would give an average AQI between 326 and 355 for the 41-day period. Except for the station at DTU (which has averaged an PM2.5-based AQI of 177 this year), the rest of the stations are still in a high range of AQI – 322 to 347, again not very different from what was there in 2019.
To be sure, as the chart also shows, only one of the 10 most polluted stations in 2019 (Jahangirpuri station) has shown deterioration in air quality since 2019, and that too marginally (0.7% growth in PM2.5 concentration). This does not mean that air quality has not deteriorated elsewhere. Four stations other than the one at Jahangirpuri – these stations were relatively cleaner in 2019 – have seen significant deterioration between 2019 and 2024. These are the stations in RK Puram (29.1% growth in PM2.5 concentration); Sonia Vihar (20.7% growth); Patparganj (3.7% growth); and Shadipur (3.2% growth).
Another aspect of air quality that one needs to read with this analysis is that none of the 33 stations analysed here show a consistent improvement. None of the 33 stations showed an improvement in all five years after 2019. This means that an improvement between 2019 and 2024 is no guarantee of the improvement being sustained in 2025.