Pollution levels rise steadily over last three years during Diwali in Tamil Nadu

A steady decline in air quality has been observed in Tamil Nadu during Diwali celebrations over the last three years. According to a comparative assessment conducted by the Tamil Nadu Pollution Control Board (TNPCB), the state's average Air Quality Index (AQI) increased by approximately 18 per cent between 2024 and 2026. An increase in noise levels in the environment was also recorded during this period.

In a list released on Monday night, the TNPCB stated that the bursting of firecrackers and changes in weather conditions are responsible for this overall increase in air pollution and noise levels. These weather changes include wind speed, wind direction, and atmospheric stability.

An investigation conducted by the Board across 39 monitoring locations in 17 districts revealed that the average AQI was 143.46 in 2024, which rose to 161.69 in 2025 and further increased to 168.97 in 2026. The highest increase was recorded in 2025, with a jump of 12.7 per cent in the average compared to the previous year. Subsequently, there was a further increase of 4.5 per cent in 2026, the TNPCB stated in the list.

This monitoring process was carried out between November 1 and 9, covering 39 air quality monitoring locations and 34 noise monitoring locations across the state. Specifically, the Diwali survey was conducted on November 8. The report's findings indicate that despite restrictions on bursting firecrackers and public awareness campaigns, air quality has been declining for three consecutive years.

Out of the 39 locations monitored in 2026, an increase in AQI was recorded at 25 places compared to 2025, while improvement was seen at 14 locations. Chennai city remained among the most affected areas, where air quality has steadily declined in several neighbourhoods over the last three years.

Looking at the figures for different areas of Chennai, Valasaravakkam recorded the highest AQI of 343 in 2026, which was 332 in 2025 and 287 in 2024. In Nungambakkam, this figure was 332 in 2026, 326 in 2025, and 230 in 2024. A more severe decline was seen in Sowcarpet, where the AQI was 193 in 2024, 260 in 2025, and 311 in 2026.

A steady increase was also observed in the T Nagar area, where the AQI was recorded as 203 in 2024, 273 in 2025, and 306 in 2026. In Triplicane, the AQI rose from 197 in 2024 to 227 in 2025 and 267 in 2026. However, Thiruvottiyur remained an exception, where the AQI, which was 207 in 2025, decreased to 183 in 2026, although it was still higher than the level of 150 recorded in 2024.

According to TNPCB data, a similar rising trend as air pollution was observed in the three-year comparison of environmental noise levels across 34 locations.