Independent report flagged misuse of studies before SO2 rollback nod

Business Standard

2 days ago

Before India significantly relaxed sulphur dioxide (SO2) emission control norms exempting a large number of coal-fired power plants, an independent analysis had warned that key scientific studies being cited to justify the move were riddled with contradictions and risked undermining public health.
In an analysis released last month, the Centre for Research on Energy and Clean Air (CREA) alleged that studies by institutions such as NEERI, NIAS and IIT Delhi were being "selectively used to justify inaction" by power plants across the country, which continue to delay the installation of flue gas desulphurisation (FGD) units to control SO2?? emissions -- a major air pollutant.
India established stringent sulphur dioxide emission standards for coal-based power plants in December 2015, requiring compliance within two years.
Even after multiple extensions, 92 per cent of coal-fired power plants have not yet installed flue gas desulphurization units to control SO2 emissions, a major air pollutant that converts into fine particulate matter (PM2.5) and causes a range of diseases.
In a notification dated July 11, the environment ministry again extended the SO2 compliance deadline for coal-based power plants located within 10 km of the National Capital Region or cities with over one million population from December 2024 to December 2027.
Plants in critically polluted or non-attainment areas will now be assessed on a case-by-case basis, while those located elsewhere have been fully exempted, provided they meet stack height criteria.
Of around 600 thermal power units in India, 462 are Category C units and 72 are Category B units.
The ministry cited "many studies" as one of the reasons for this move, along with techno-economic concerns, COVID-related delays and a recommendation from the Ministry of Power.
CREA's report, titled "From scientific evidence to excuses", countered this reasoning and said: "What is worse, studies by institutions like NEERI, NIAS, and IIT Delhi (2022 and 2024) are now being selectively used to justify this inaction, citing low SO2 levels or small CO2 increases to argue that FGDs are unnecessary. These arguments simply don't hold up." CREA said NEERI's assertion that ambient SO2 levels are already low is "highly misleading".
"The air quality monitoring stations (CAAQMS) do not capture the real impact of power plant pollution because they do not track whether emissions drift upwind or downwind and they certainly do not account for chemical reactions that convert SO2 into other pollutants like PM2.5. Just because the station reading is low ambient SO2 does not mean the plant is not polluting," the report said.
It said that SO2 emission norms and the requirement to install FGDs are based on stack emissions, not on ambient SO2 levels. "Using low ambient readings to argue against FGD is not just scientifically wrong, it completely misleads how pollution control works".
Ironically, CREA noted, the NEERI report being used to question the utility of FGDs had itself acknowledged, "if a flue gas desulfurization technique is installed to reduce sulphur emissions from thermal power stations, it will reduce a part of it, and the overall reduction in ambient air PM will be at most 20 micrograms per cubic metre." CREA said that this would translate to a 20 per cent reduction in cities where PM2.5 levels are around 100-120 micrograms per cubic metre.
Similarly, the 2022 IIT Delhi report concluded that "with the implementation of FGD in the Vindhyachal TPP, we can expect to see a decrease in the monthly mean surface concentrations of sulfate aerosols in the range of 10-15 per cent of the climatological values at certain places as far as 100 km from the location of this TPP".
The IIT Delhi report added: "Significant decreases in sulfate aerosol concentrations are also observed as far as 200 km from the TPP".
CREA noted that despite these findings, a 2024 IIT Delhi report narrowed its scope to six cities and recommended halting FGD rollout in plants that have yet to adopt it.
The analysis also highlighted that "coal-fired power plants led to 47,000 deaths in 2014; 62,000 deaths in 2017 and 78,000 deaths in 2018", and warned that "it is very likely that the health impacts would be much worse than what is being estimated now" as India plans to add 80-100 GW of new coal-fired capacity.
A NIAS report previously estimated that full FGD implementation would add "approximately 23 million tonnes of CO2 by 2030, which is just 0.9 per cent of India's total CO2 emissions in 2020".
CREA said it is comparable to "the output of a single coal-based power plant with over 3 GW capacity".
The analysis added that "the irony lies in the fact that while this marginal CO2 increase by FGD is criticised, plans to build an additional 80 to 100 GW of coal capacity, which would result in far greater CO2 emissions, are not questioned with the same urgency".
On the claim that FGD installations cause prolonged shutdowns, CREA said: "NTPC RTI data shows that most FGDs were fitted during regular maintenance, with no additional shutdown period." NTPC, it added, had already installed FGDs in plants with 20 GW capacity and had another 47 GW under construction.
CREA said the latest studies by IIT Delhi and IIT Bombay confirmed that "power plants are a leading cause of India's air pollution", contributing up to 12 per cent of PM2.5 during winter and 16 per cent of cross-boundary urban pollution.
It added that this level of contribution is "on par with the vehicle sector, where the country went through a national initiative to switch to BSVI many years before".
"Since emissions from coal-fired power plants have long-range impacts, affecting air quality at the national level, FGD installation should be mandatory across India, regardless of plant location," the research organization said.
FGDs are a critical, life-saving tool that India should have deployed years ago. Every delay means "more lives lost, more children breathing toxic air, and more communities suffering from preventable disease", it cautioned.
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