Context
- The Union Environment Ministry has exempted 78% of India’s 600 thermal power plant (TPP) units from installing Flue Gas Desulphurisation (FGD) systems.
- FGD systems are critical for reducing sulphur dioxide (SO₂) emissions, a precursor to acid rain and particulate matter (PM2.5) pollution.
- Only about 11% of thermal plants — those in high-density/population areas — are still mandated to install FGD systems.
Relevance : GS-3 – Environment and Energy; air pollution, public health, and emission standards.
What are FGDs and Why Do They Matter?
| Feature | Description |
| Purpose | Reduces SO₂ emissions by up to 95% from coal combustion |
| Mechanism | Uses limestone slurry or seawater to scrub sulphur oxides from flue gas |
| Relevance | SO₂ contributes to PM2.5 formation, acid rain, respiratory and cardiac diseases |
| Global Practice | Mandatory in China, US, EU for all coal-fired plants since early 2000s |
India’s Thermal Power Pollution Profile
| Indicator | Value |
| Total TPPs | ~180 (comprising 600+ units) |
| Share in electricity | ~72% of total generation (as of 2025) |
| Share in SO₂ emissions | ~51% of all industrial SO₂ |
| Plants with FGD installed | Only 8% (mostly NTPC-run) |
| Exempted units post-policy | ~468 units (78%) |
Key Policy Update (July 2025)
| Category | Criteria | FGD Mandate |
| Category A | Within 10 km of NCR or Tier-1 cities | Mandatory |
| Category B | Within 10 km of Critically Polluted Areas (CPAs) or Non-Attainment Cities (NACs) | Case-by-case |
| Category C | All others | Exempted |
Result: Only ~11% (Category A) will remain under FGD norms.
Basis for Exemption: What Experts Said
The government relied on recommendations of a scientific panel led by Principal Scientific Adviser Ajay Sood:
- Claimed Indian coal has low sulphur content
- Found no major SO₂ difference in areas with or without FGDs
- Argued that sulphates suppress warming, so removing SO₂ may increase net radiative forcing
Counterarguments by Public Health & Environmental Experts
| Argument | Response |
| “Indian coal is low in sulphur” | But still emits enough SO₂ to drive PM2.5 in hotspots |
| “FGDs don’t improve local air quality” | Air quality impact depends on meteorology; long-range transport of SO₂ is well documented |
| “Sulphates cool the planet” | True — but co-benefits of SO₂ do not outweigh public health costs (respiratory illness, strokes) |
| “FGDs are costly” | Health costs of SO₂ are 5x higher than installation costs (per WHO/ICMR studies) |
Global Standards vs India’s Position
Implications of the Decision
- Environmental:
- Higher SO₂ emissions → elevated secondary particulate matter (sulphates)
- Weakens India’s commitment to air quality improvement under NCAP
- Potential rise in acid rain impacting crops, soil, monuments
- Public Health:
- Risk of increased respiratory and cardiovascular illnesses
- Higher disease burden in rural areas near exempted plants
- Economic:
- Disincentivises green tech investment in the power sector
- Short-term relief for discoms & thermal producers, but long-term cost-shifting to health sector
- Global Commitments:
- May impact India’s COP pledges on emissions intensity
- Could weaken diplomatic stance on climate finance and clean tech if domestic credibility erodes
Way Forward: Balancing Power and Pollution
- Reprioritise Targeted FGDs: Mandate for plants near dense populations, agricultural belts, and ecological hotspots.
- Subsidised Technology Deployment: Viability gap funding for older plants; tie to ESG-linked financing.
- Integrated Emissions Tracking: Mandatory online SO₂, NOx, PM reporting on public dashboard.
- Health Cost Valuation: Incorporate externalities into tariff-setting by CERC.
- Accelerate Renewables: Reduce dependence on coal by scaling solar-wind-battery hybrids.
