CHENNAI: With the state government slowly easing COVID-19 lockdown norms to restore some normalcy, Chennai's pollution woes have returned. On Tuesday, the city's Air Quality Index (AQI) was 116, which was the worst among all major southern cities.
In comparison, Bengaluru recorded an AQI of 77, Hyderabad 73, Kozhikode 21 and Thiruvananthapuram 58. An AQI between 0 and 50 is considered 'good', 51 and 100 'satisfactory' and 101 and 200 'moderate'.
Chennai's air quality showed a positive shift in AQI during the lockdown compared to 2019. As per the Central Pollution Control Board (CPCB) analysis released recently, the city has reported improved AQI with 26 'good' days as against four such days in 2019.
The number of 'satisfactory' days reduced to 14 as against 31 in 2019 with more days shifting to the good category during lockdown and zero moderate days were reported as against five moderate days last year. In fact, Chennai had done fairly well during the lockdown compared to other cities in the country.
However, now with lockdown restrictions relaxed to a large extent, pollution is peaking once again. Alandur in Chennai has recorded poor air quality with the AQI breaching the 200 mark. At 3 pm, the AQI was 218 and PM2.5 concentration spiked as high as 500 µg/m3 (micrograms per cubic metre), which is extremely hazardous.
When contacted, Tamil Nadu Pollution Control Board (TNPCB) Chairman AV Venkatachalam told The New Indian Express that the state government was investing heavily on air quality monitoring.
"A total of 25 Continuous Ambient Air Quality Monitoring Stations (CAAQMS) have been installed and calibrated. The Chief Minister will be inaugurating them soon. Of these, four real-time monitors are installed in Chennai at Perungudi, Kodungaiyur, Koyambedu and Royapuram. The inputs from these stations will be integrated with CPCB stations and generate AQI for Chennai," the official said.
Officials said as overcast conditions have been forecast over Chennai with light showers, the pollution levels are likely to remain in the moderate category for a couple of days as dispersion of pollutants would be slow.
Sagnik Dey, associate professor at Centre for Atmospheric Sciences in IIT Delhi, said every source apportionment study shows that there are eight key sources of pollution in India -- power plants, vehicles, industry, household, brick kilns, open burning, diesel power generators & dust (from construction, soil, resuspended and trans-border).
Of these eight sources, only four were shut down during the
lockdown -- vehicles, industrial activity, brick kilns and construction activity. Meanwhile, power plants are still on, household activity might even be on the increase due to the population being home-bound, open burning is still happening, as well as diesel power generators.
"So clearly, this reduction in pollution in India during the lockdown has come from the other four major sources. If we can control vehicular, industrial, brick kilns and construction activity, we can reach the PM2.5 and PM10 targets in the near future."
Only recently, Transport Commissioner TS Jawahar told the National Green Tribunal here that the Tamil Nadu government has a definitive plan to address the problem of vehicular emissions. He said the government had planned to give 100 per cent tax exemption and waive permit fees for all EV vehicles till December 30, 2022.
The official also said the government was making efforts to set up grid charging stations in six major cities -- Chennai, Coimbatore, Trichy, Madurai, Salem and Tirunelveli. "The charging stations will be set up at every 25 km distance on both national and state highways. EV related and charging infrastructure manufacturing industries in the state will be provided 100 percent exemption on electricity tax till December 31, 2025 and also stamp duty exemption during purchase of land," Jawahar said.