The recent discourse around air pollution in Chennai has left me distressed and angry. We are being told that there is a spike in pollution, that we now need to be worried and that this spike is a result of Delhi’s air pollution.
Once again, northern conspirators with their collaborators in the south are making it appear as though we, in the peninsula, could never get anything going on our own. Everything was to be a hand-me-down, even pollution. You forget, my friend, that Tamil Nadu is the most urbanised and industrialised large state in the country, with more than 37,000 factories within its borders.
Our Pollution Control Board is as inept and pliant a regulator as any. Honouring its aggressive defence of polluters and pollution even in the face of science, we affectionately refer to the agency simply as the ‘Pollution Board’. Control is for wimps.
With all this going for it, why in the hazy world would Chennai’s air pollution depend on the great South Asian pollution plume, with its epicentre in some obscure Hindi-speaking northern city? Trying to give stubble-burning farmers from Punjab and Haryana all the credit for the air pollution in Chennai is literally the last straw.
We won’t let this happen. Science, data and Tamil pride simply won’t allow that.
Was there a spike?
I looked at Central Pollution Control Board’s air pollution data – specifically PM 2.5 levels – at IIT-Madras, Alandur and Manali monitoring stations for the 365 days ending November 5, 2019.
PM 2.5 refers to microscopic particulate matter that is less than 2.5 micrometres in size. Because of its ability to penetrate deep into the lung tissue, and exert highly toxic effects, PM 2.5 is a good indicator and measure of pollution.
World Health Organisation prescribes a standard of 25 ug/m3 in air as a level that is generally safe. To achieve the triple goals of development, environmental protection and population control, India has fixed a far laxer standard – 60 ug/m3.
PM 2.5 pollution levels of 61 to 90 ug/m3 is referred to as “moderately polluted”; PM 2.5 levels of 91 to 120 as “Poor”; 121 to 250 as “Very Poor”; and above 250 ug/m3 as “Severe."
Table: PM 2.5 levels from 1 November to 5 November 2019
The above table suggests that there was indeed a spike from November 3 to November 4. But if you were not alarmed at the levels before the spike, then there is no need to be alarmed by the spike either. In IIT-Madras and Alandur, for instance, pollution worsened from “Moderately Polluted” to “Poor.” In Manali, it worsened from “Poor” to “Very Poor.”
Is this abnormal?
If you want to be like Delhi and celebrate every time air quality changes from “Severe” to “Very Poor”, go ahead and dig your own grave. But science says your celebration is baseless. Consistent exposure to even “moderately polluted” air will knock years off your life. One study found that average life span increases by four months for every 10 ug/m3 drop in PM 2.5.
The levels recorded from November 3 to 5 ranged from “Very Poor” to “Poor”. If it weren’t for Delhi, we wouldn’t have even noticed it. Considering our sunny outlook to life and seeing half-full cups and all that, it’s not as if we would know the difference between good air and bad.
And besides, we are trained from childhood that panicking and saying things that may cause alarm, even if such alarms were warranted, is an irresponsible act that only anti-nationals and urban naxals would indulge in.
So I looked at the PM 2.5 levels in the three CPCB stations in Chennai for 365 days ending November 5, 2019, to see if the levels were particularly bad this last week.
The data from Manali station recorded 119 days when air quality was unacceptable, and exceeded even the lax Indian standard for PM 2.5. Of this, 13 were days when PM 2.5 levels ranged from “Very Poor” to “Severe”. Only one of these 13 days fell in the last week when all the noise about Chennai choking because of Delhi was being made. Ditto with Alandur, which recorded four days of “Very Poor” and four days of “Severe” pollution in the last year. Only one out of four days fell in the last week, and none of the four severely polluted days when air pollution was above 250 ug/m3 fell in the last week.
If Alandur’s numbers are anything to go by, February and March 2019 were the worst months, containing all four severely polluted days when PM 2.5 levels recorded were 392 ug/m3 on February 14, 504 ug/m3 on February 26, 325 ug/m3 on February 28, and 672 ug/m3 on March 1.
If those numbers did not alarm us, the current numbers should not either.
The only thing abnormal about the November air is the amount of noise being made over routine air pollution choking the city like it always has.
Can Delhi take credit for choking Chennai?
Absolutely not. With 3,300 MW of coal-fired thermal power plants and a 10 million tonne per annum petroleum refinery within Chennai’s metropolitan area, we are fully capable of poisoning our city with no help from others. Thank you very much.
It is true that pollution plumes do move long distances and may elevate pollution levels marginally, particularly in unpolluted areas. However, it is highly unlikely that such plumes will cause a noticeable spike in polluted areas like Chennai city.
That is particularly so when the sources of pollution closest to our city have been doing a great job of discharging pollutants well in excess of emission standards.
I looked at TNPCB’s Care Air Centre real time air monitoring data from NTPC’s Vallur power plant and TANGEDCO’s North Chennai Thermal Power Station. I was able to download the emission data from some of the smokestacks in these two industries for a 10.5 hour period ending 10.30 am on November 6, 2019.
Emissions of oxides of Nitrogen from NTPC Unit 3 and Unit 1 were consistently above the prescribed standard of 300 mg/m3 and ranged between 525 and 620 mg/m3 – more than twice the accepted levels.
NTPC Unit 1 data
NTPC Unit 3 data
Sulphur dioxide levels for the same duration ranged from 910 to 1000 mg/m3 – the maximum recordable by the SO2 sensor – for Unit 3. Meanwhile, Unit 1’s emissions were consistently above the highest detection limit of the sensor and clocked a steady 995.9 mg/m3.
TANGEDCO’s Unit 2 spewed particulate matter (PM) at between 125 and 180 mg/m3 against an emission standard of 100 mg/m3. SO2 levels from this unit ranged between 290 and 335 ppm against a standard of 76 ppm with not one instance when SO2 emissions were compliant. Oxides of nitrogen ranged from 380 to 420 ppm against a threshold of 159 ppm.
TANGEDCO Unit 2 data
TANGEDCO’s Stage 2’s second chimney registered SO2 levels between 320 and 360 ppm against a prescribed threshold of 76 ppm, and NOx levels of 375 to 425 ppm against a threshold of 159 ppm.
TANGEDCO Stage 2’s second chimney data
Until 2017, there was some unintended mitigation of the pollution from TANGEDCO’s two stages because of a 150 acre forest that was shown as part of the statutory greenbelt prescribed as part of the Environmental Clearance. In 2017, that greenbelt was mowed down for setting up a new power plant NCTPS Stage 3. The matter was challenged in the National Green Tribunal even before the forest was lost. In the few months that it took the slow-moving judge to even serve notice, the trees were gone. The matter is still pending before the lordships in New Delhi. Some poetic justice.
What about TNPCB’s assurance?
In an interview to The Hindu about the November smog, a Pollution Board official said: “There is nothing to be alarmed of. These levels of PM 2.5 are only temporary due to the weather.”
Tell that to your distressed lungs, and see if the official’s calm confidence helps soothe the burning tissue.
Going well beyond the call of duty, the official also reassured people that they “are continuously monitoring industries and taking steps to reduce emission levels if they cross levels.”
Wow. Really! I just monitored the TNPCB’s monitoring system, and found that emission levels have indeed crossed levels, including maxing out at more than 1000 mg/m3 of SO2 at Units 1 and 3 of NTPC’s plant in Vallur (refer charts above).
To see if they were continuously monitoring, I looked at the real time monitoring data from the 43 sensors located atop more than a dozen stacks at the Chennai Petrochemical Ltd’s (CPCL) refinery in Manali. Not one of the monitors was functioning.
Next time you have difficulty breathing, just think of the calm Pollution Board official and repeat the 3 Idiots mantra – All Is Well!!
Nityanand is a Chennai-based writer and social activist. Views expressed are the author’s own.