CHENNAI: The city woke up to “very poor” air quality on the morning after Deepavali, with Valasaravakkam recording an Air Quality Index (AQI) of 343, followed by Nungambakkam (332), Sowcarpet (311), and T Nagar (306), according to the Tamil Nadu Pollution Control Board (TNPCB). An AQI value between 301 and 400 falls under the very poor category, with prolonged exposure potentially causing respiratory illness.
The TNPCB, which conducted the Deepavali air quality survey during the 24 hours till 6 am on November 9, attributed the overall increase in air pollution and ambient noise levels to the bursting of crackers and the variations in meteorological conditions, including wind speed, wind direction and atmospheric stability.
Meanwhile, due to thick smog, an IndiGo flight from Raipur was diverted to Bengaluru because of difficulty landing. Also, a few other flights were delayed.
A comparative analysis of the TNPCB’s monitoring data for the past three years indicated that 2026 recorded the highest average AQI during Deepavali across the 39 monitoring locations in 17 districts. The statewide average rose to 168.97 in 2026 from 161.69 in 2025 and 143.46 in 2024, marking a 4.5% increase over the previous year. Of the 39 locations monitored, 25 recorded an increase in AQI compared with 2025, while 14 registered a decline.
The deterioration was particularly pronounced in several Chennai neighbourhoods. In Nungambakkam, the AQI rose from 230 in 2024 to 326 in 2025 and to 332 this year. Valasaravakkam recorded 287 in 2024, 332 in 2025, and 343 in 2026. Sowcarpet witnessed a sharper increase, from 193 in 2024 to 260 in 2025 and 311 this year. T Nagar’s AQI increased from 203 in 2024 to 273 in 2025 and 306 in 2026.
Triplicane also recorded a steady increase, with its AQI rising from 197 in 2024 to 227 in 2025 and 267 this year. Besant Nagar, however, saw its AQI rise to 230 this year after declining to 190 in 2025 from 220 in 2024. Thiruvottiyur recorded an AQI of 183 this year, lower than the 207 recorded in 2025, but higher than the 150 recorded in 2024.
Meanwhile, separate data from the Greater Chennai Corporation’s (GCC’s) network of 75 monitoring sensors showed a sharp deterioration in air quality following the festival. The average AQI across the available readings rose from 41.2 on November 6 to 94.6 on November 7 and 188.4 on November 8, before surging to 361.4 by around 10 am on November 9.
The November 9 figure is a partial-day average and should not be treated as a full-day reading. The GCC analysis identified Kallikuppam as the location with the highest average AQI (275.6) on November 8, followed by Oragadam in Ambattur at 273.6, Valasaravakkam at 264.3, Triplicane at 261.8, and Ernavoor at 261.
Equally, the TNPCB has reported an increase in noise levels across 34 monitoring locations in the state. In GCC, the board recorded the highest noise level of 88.6 dB(A) at Valasaravakkam and the lowest of 77.4 dB(A) at Thiruvottiyur on Deepavali day between 6 pm and midnight.
The comparative data also showed high noise levels at several other Chennai neighbourhoods. Besant Nagar recorded 85.5 dB(A), while Sowcarpet and Valasaravakkam recorded 84.6 dB(A) each, according to the location-wise table in the TNPCB report.
House gutted, eight vehicles damaged
A house in Sriperumbudur and eight vehicles across the Chennai region were gutted by fire in firecracker-related incidents over the two days till Monday. The occupants of the house escaped before the fire spread. In Kumananchavadi, a car and four two-wheelers were damaged in firecracker-related incidents.
Meanwhile, in Adambakkam, a car and two two-wheelers were completely destroyed in fire triggered by the bursting of crackers. Tamil Nadu Fire and Rescue Services Department received a total of 117 calls related to firecracker accidents across the state on Deepavali day (Sunday) and Monday (till 8 pm).