THE CONTEXT: On 10 July 2025 the Ministry of Environment, Forest and Climate Change (MoEFCC) issued a notification exempting 78 % of India’s 600 coal-based generating units from installing Flue-Gas Desulphurisation (FGD) systems; only units within 10 km of million-plus cities or the National Capital Region must comply by 2027. The order reverses the 2015 mandate that sought full FGD retrofits by 2017, repeatedly deferred to 2024.
EVOLUTION OF INDIA’S SO₂ REGULATION:
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- 1986-2003: Environment (Protection) Rules prescribe stack-height formulas but no explicit SO₂ cap.
- 2015: MoEFCC notification under the Environment (Protection) Act, 1986 sets an SO₂ limit of 200 mg Nm⁻³ and requires wet-FGD for all existing plants.
- 2017-24: Deadlines slip thrice; only 8 % units (mainly NTPC) install FGD.
- July 2025: Category-wise dilution (A: mandatory; B: conditional; C: exempt).
DEMYSTIFYING FLUE-GAS DESULPHURISATION (FGD):
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- FGD is a post-combustion technology that sprays a limestone slurry into flue-gas, converting SO₂ to gypsum and achieving 90-95 % removal.
- Capital cost for a 500 MW unit is ₹5–6 crore per 100 MW; power-tariff impact is 6–8 paise kWh⁻¹ (CEA estimate, 2024).
- China retrofitted 98 % of capacity to similar wet-FGD between 2014 and 2020, capping SO₂ at 35 mg m⁻³.
HEALTH-VS-CLIMATE TRADE-OFF: WHAT DOES THE SCIENCE SAY:
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- Short-term exposure to SO₂ triggers bronchoconstriction; WHO 2021 guideline is 40 μg m⁻³.
- Sulphate aerosols offset 0.4 °C of anthropogenic warming but raise chronic cardiopulmonary mortality.
- EPA Acid Rain Programme shows > 95 % SO₂ cut delivered benefits worth US$ 120 b yr⁻¹ against US$ 3 b yr⁻¹ compliance cost. Hence climate co-benefit arguments for SO₂ retention are scientifically weak because aerosol cooling is transient and region-specific.
WHY THE ROLLBACK? — POLITICAL-ECONOMY DRIVERS
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- Cost-avoidance: ₹1.8 lakh crore capex saved; discoms oppose tariff hikes.
- Vendor bottleneck: Only 6 turnkey FGD suppliers in India; pandemic-era supply chain shocks.
- Power security narrative: Coal provides 73 % of generation; Ministry of Power argued FGD retrofits could curtail 5–6 GW during outages.
- New advisory: Principal Scientific Adviser’s committee claimed low sulphur in domestic coal (0.4 %) and negligible sulfate formation.
FEDERAL EQUITY & CONSTITUTIONAL LENS:
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- Creating three categories of protection undermines Article 14 (equality before law) and Article 21 (right to life and clean air).
- The Centre’s power to set uniform “minimum” standards under Section 3(2)(v) of the Environment Act is diluted, raising cooperative-federalism tensions, especially for down-wind states affected by trans-boundary transport of SO₂ (model studies show 200 km footprint).
WHAT THE WORLD IS DOING:
| Country / Region | Compliance Tool | Outcome |
|---|---|---|
| China | Ultra-Low Emission (ULE) norm: SO₂ ≤ 35 mg m⁻³ by 2020; feed-in tariff premium for early movers. | National SO₂ fell 65 % between 2014-17. |
| United States | Cap-and-trade under Title IV (Acid Rain Program). | 95 % SO₂ cut, cost < ⅓ of original projection. |
| European Union | Industrial Emissions Directive (IED) with Best Available Techniques Reference (BREF). | Uniform 200 mg Nm⁻³ ceiling, declining to 150 mg Nm⁻³ post-2028. |
THE ISSUES:
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- Externalities not internalised: Health damages (₹10 per kWh) dwarf retrofit costs but are borne by public health budgets.
- Weak Continuous Emission Monitoring System (CEMS): Calibration lapses, data gaps > 25 % undermine compliance.
- Stack-height fallacy: 275 m stacks merely export pollution; dry season inversion layers return sulphates at respirable heights.
- Regulatory silo: MoEFCC sets norms; Central Electricity Authority governs generation; CPCB monitors creates diffused accountability.
- Penalty laxity: Non-compliance fines (up to ₹20 crore) rarely imposed; deadlines perpetually extended.
- Financing gap for state GENCOs: High debt-equity ratios, weak credit rating, absence of green-bond window.
CASE STUDIES:
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- NTPC Dadri, Uttar Pradesh: First retrofit (500 MW unit) commissioned in 2023; observed stack SO₂ cut from 1,200 mg Nm⁻³ to 120 mg Nm⁻³; tariff rise 7 paise kWh⁻¹.
- Vindhyachal Super Thermal Power Station, Madhya Pradesh: FGD EPC contract delayed by land constraints and limestone logistics; cost escalation 18 %.
THE WAY FORWARD:
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- Differential Renewable Purchase Obligation (RPO) Surcharge: Levy a 5-paisa clean-air cess on Category C units and earmark proceeds for FGD capex grants in pollution hotspots. This internalises externalities without steep tariff shock.
- Green-Corridor Limestone Logistics: Prioritise dedicated rail rakes from Rajasthan and Andhra Pradesh limestone belts to thermal clusters, slashing sorbent delivered cost by 12 %.
- Real-time CEMS Blockchain Registry: Mandate tamper-proof blockchain logging of flue-stack sensors, enabling transparent public dashboards and citizen litigation triggers.
- Bundle FGD with Carbon Capture Pilot: Encourage hybrid scrubber-plus-amine modules that harvest CO₂-rich flue-gas after SO₂ removal, cutting capture costs 15 %.
- Limestone Gypsum Circularity: Create a reverse-auction portal for FGD gypsum to cement plants, offsetting 20 % retrofit O&M costs.
- Regional Emission Trading Scheme (RETS): Pilot a cross-state SO₂ cap-and-trade in the eastern coal belt, learning from Gujarat’s PM ETS.
- Tiered Stack-Tax: Impose escalating emission fee per mg Nm⁻³ above 200 mg; revenues ring-fenced for NCAP city action plans.
- Cross-over Tariff Pass-Through Clause: Amend Electricity Act tariff regulations allowing automatic pass-through of verified FGD cost, reducing discom litigation delays.
- Community Exposure Mapping: Integrate NCAP low-cost sensor grid with epidemiological cohorts to quantify health co-benefits and build public pressure.
- Accelerated Depreciation Incentive: Allow 40 % first-year depreciation on FGD capex, improving project IRR by 1.8 percentage points.
- Time-bound Sunset Clause Review: Mandate MoEFCC to table a peer-reviewed impact report in Parliament by 2028 before extending any further exemptions.
THE CONCLUSION:
Dilution jeopardises SDG 3 (Good Health and Well-being) and SDG 13 (Climate Action) targets, contradicts the National Clean Air Programme target of 40 % PM reduction by 2026, and weakens India’s credibility in G-20 “Clean Energy Transitions” track. The decision also risks conflict with state-level action plans under the Fifteenth Finance Commission’s health-linked grants, creating fiscal dis-incentives for proactive states.
UPSC PAST YEAR QUESTION:
Q. Environmental impact assessment studies are increasingly undertaken before project is cleared by the government. Discuss the environmental impacts of coal-fired thermal plants located at Pitheads. 2014
MAINS PRACTICE QUESTION:
Q. Exemption of most coal-fired power stations from installing Flue-Gas Desulphurisation systems is defended on economic and climate grounds. Analyse this decision in the light of public-health and India’s international commitments.
SOURCE:
https://www.thehindu.com/opinion/editorial/smoke-and-sulphur/article69807534.ece
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