India has extended the Sulphur Dioxide (SO₂) emission deadline for thermal power plants by another three years, citing high costs and logistical challenges in installing Flue Gas Desulfurization (FGD) systems. Despite being the world’s largest SO₂ emitter, with coal-fired power plants as the primary source, only 8% of plants have adopted SO₂ control technologies. Challenges include limited domestic production, supply constraints and rising costs, leading to repeated deadline extensions. The delay threatens environmental and public health, increases electricity costs and raises concerns over India’s commitment to air quality regulations.
Sulphur dioxide (SO₂) is a heavy, colourless and poisonous gas with a pungent, irritating odour. It plays a significant role in air pollution, as it oxidizes to form sulphuric acid (H₂SO₄) by reacting with water vapour, leading to the formation of secondary particulate matter (PM2.5). Additionally, it reacts with ammonia (NH₃) to produce ammonium sulphate ((NH₄)₂SO₄) which is a harmful compound contributing to atmospheric pollution. SO₂ is also a major factor in sulphurous smog, which results from high concentrations of sulfur oxides (SOx) in humid conditions and is worsened by particulate matter (PM). The primary sources of SO₂ emissions include burning fossil fuels such as coal and oil in domestic heating, transportation (especially locomotives and ships), power plants and industrial facilities. Additionally, smelting sulphur-containing mineral ores like iron pyrite and copper pyrite releases significant amounts of SO₂. Natural sources, such as volcanic eruptions, also contribute to its atmospheric presence.
SO₂ is a precursor to the formation of fine particulate matter (PM2.5), which has been linked to severe health issues, including respiratory and cardiovascular diseases. Exposure to high levels of SO₂ can irritate the eyes, throat and lungs, aggravating conditions such as asthma and bronchitis. Long-term exposure is associated with an increased risk of heart attacks, strokes and premature death. Moreover, SO₂ contributes to the formation of acid rain, which can damage ecosystems and harm aquatic life.
REPORT: STATISTA
India emitted approximately 11.2 million metric tons of Sulfur Dioxide (SO₂) in 2022. This accounted for roughly 20 percent of global SO₂ emissions that year, making India the world's biggest emitter of Sulfur Dioxide primarily due to its heavy reliance on coal for electricity generation. Russia followed closely in second. India has the highest SO₂ emissions from electricity generation, at 6,807 kilotonnes, followed by Turkey (2,206 kilotonnes) and Indonesia (2,017 kilotonnes).
Five of the top ten SO₂ emission hotspots from coal and power generation are located in India. The Greenpeace study finds that Singrauli, Neyveli, Talcher, Jharsuguda, Korba, Kutch, Chennai, Ramagundam, Chandrapur and Koradi are the major SO2 emission hotspots in India.
As of September 2024, India has an installed electricity generation capacity of 452 GW. Coal-fired power plants (CFPPs) hold the largest share of this capacity, with 211 GW (47%), followed by renewable energy sources at 34%, hydro at 10%, gas at 5%, nuclear at 2%, lignite at 1% and diesel at less than 1%.
Satellite data analysis shows an increase in sulphur dioxide (SO₂) levels in India in 2023 compared to 2019, with a notable rise in regions dominated by coal-fired power plants (CFPPs), highlighting the influence of power plant emissions on air quality.
4,327 kilotonnes of SO₂ were released by 537 coal-fired power plants units from June 2022 to May 2023 accounting for approximately 36% of the total emissions.
FGD removes sulfur compounds from power plant emissions by using absorbents, eliminating up to 95% of SO₂ from flue gas, which is produced when fossil fuels are burned.
CFBC reduces SO₂ and NOₓ emissions by injecting air and lime during combustion. The process fluidizes solid particles, enhancing fuel efficiency and lowering pollution.
Earlier, thermal power plants (TPPs) were regulated only for particulate emissions, with no specific norms for SO₂, NOₓ and mercury emissions. Standards focused solely on chimney height to aid dispersion. However, on December 7, 2015, the MoEF&CC introduced stricter environmental norms for coal-based TPPs under the Environment (Protection) Act, 1986 to control these pollutants.
Following the December 2015 notification of new environmental norms, the Central Electricity Authority (CEA) devised a phased plan for Flue Gas Desulfurization (FGD) installation, targeting completion by 2024 in consultation with stakeholders. However, in June 2017, the Ministry of Environment, Forest and Climate Change (MoEF&CC) revised the deadline, accelerating it to December 2022.
On December 30, 2024, the Ministry of Environment, Forest and Climate Change (MoEFCC) announced that thermal power plants now have three more years to follow rules that limit sulphur dioxide (SO2) pollution. However, the government did not give a reason for this delay.
India's coal has low sulphur content, so meeting SO2 limits should have been easy. However, power plants need to install a special machine called Flue Gas Desulphurisation (FGD) to remove SO2. This became a problem because:
Less than 8% of India's coal-based power plants have implemented Flue Gas Desulfurization (FGD) and Circulating Fluidized Bed Combustion (CFBC) technology, as recommended by the Ministry of Environment, Forest and Climate Change (MoEF&CC), according to the Centre for Research on Energy and Clean Air (CREA). Only 16.5 GW of coal plants have installed FGDs, while CFBC boilers cover 5.9 GW. This highlights that 92% of India's coal power plants still operate without FGDs. Since December 2022, only 3.2 GW of additional capacity has adopted SO₂ control technologies.
The blanket extension of deadlines by MoEF&CC and CPCB, without assessing plant progress, significantly derailed emission control efforts in coal-based power plants.
Increase in CO₂ Emissions and Power Consumption
One mole of CO₂ is released per mole of SO₂ absorbed in FGD processes. The wet limestone desulfurization method, while cost-effective, adds 0.5% more CO₂ emissions due to complete neutralization. Furthermore, coal consumption may increase by 1%, leading to additional greenhouse gas emissions, reduced power plant efficiency and an overall negative impact on global warming and climate change.
Focus on Ambient Air Quality (AAQ) Instead of Uniform Norms: Emission standards should be based on local air quality rather than one-size-fits-all norms.
Prioritization Based on SO₂ Levels:
In 2021, the MoEF&CC categorized coal power plants based on geography to enforce staggered deadlines:
Most power plants fall under Category C, while stricter deadlines apply to urban areas due to higher pollution risks.
Also, categorization does not consider actual SO₂ or NOₓ levels. Many cities suffer from PM10 and PM2.5 pollution, but not necessarily SO₂ or NOₓ emissions. Conversely, high SO₂ areas outside these zones might be overlooked.
Some experts say that SO2 rules should be applied slowly, rather than all at once. Studies by IIT Delhi and NITI Aayog also debated whether India should focus more on dust pollution instead of SO2.
In short, different agencies have raised concerns about uniform SO2 norms across India:
Flue-Gas Desulfurisation (FGD) Technology Can Cut SO₂ Emissions by 67%Installing Flue-Gas Desulfurisation (FGD) technology in 12 coal-based thermal power plants within 300 km of Delhi could reduce sulphur dioxide (SO₂) emissions by 67%, according to a study by the Centre for Research on Energy and Clean Air (CREA). At the national level, implementing FGD systems could bring down SO₂ emissions from 4,327 kilotonnes to 1,547 kilotonnes, marking an overall 64% reduction. This underscores the significant impact of FGD technology in reducing air pollution from coal-fired power plants (CFPPs). |
MoEFCC has now extended the deadline four times. The latest extension means:
The continuous regulatory delays have financial implications for electricity consumers:
The failure to enforce SO2 norms raises concerns about:
Despite over a decade of policymaking, India’s approach to SO2 regulation remains incomplete—much like Birbal’s khichdi, which never gets fully cooked.
With time running out, ensuring clean coal power is not just about regulations—it is a commitment to cleaner air and a healthier future.
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PRACTICE QUESTION Q.Analyze the impact of India's repeated SO₂ emission deadline extensions for thermal power plants on public health, the environment and air quality commitments. Suggest solutions. |
FAQs
1. Why is India the largest emitter of sulphur dioxide in the world?
India emits the highest SO₂ globally due to its heavy reliance on coal-fired power plants.
2. Which are the top SO₂ emission hotspots in India?
Major hotspots include Singrauli, Neyveli, Talcher, Jharsuguda, Korba, Kutch, Chennai, Ramagundam, Chandrapur and Koradi, as identified by satellite data.
3. How much SO₂ do India’s coal power plants emit annually?
Between June 2022 and May 2023, Indian coal-fired power plants emitted 4,327 kilotonnes of SO₂, accounting for 36% of total national emissions.
4. What technologies can reduce sulphur dioxide emissions from power plants?
Flue Gas Desulfurization (FGD) and Circulating Fluidized Bed Combustion (CFBC) can reduce SO₂ emissions by up to 95%.
5. What are India’s SO₂ emission norms for coal-fired power plants?
Introduced in 2015 by MoEF&CC, these norms mandate FGD installation to control SO₂ emissions, but deadlines have been repeatedly extended.
6. Why has India struggled to implement SO₂ control measures?
Challenges include high FGD costs, supply chain constraints, slow installation, lack of domestic manufacturing and regulatory delays.
7. How many coal power plants in India have installed FGD technology?
As of 2024, only 16.5 GW of coal plants have FGDs, meaning 92% of India’s coal power plants still lack SO₂ control systems.
8. Has India extended its SO₂ emission deadline for power plants?
Yes, the deadline has been extended four times, with the latest extension pushing compliance to December 30, 2024.
9. How does the delay in SO₂ norms affect electricity consumers?
The delay increases electricity costs as power plants pass FGD expenses to consumers, while pollution remains uncontrolled.
10. Can FGD technology significantly reduce SO₂ emissions in India?
Yes, if implemented across India, FGDs could cut SO₂ emissions by 64%, drastically improving air quality and reducing pollution-related health risks.
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