Context
On July 11, 2025, the Union Environment Ministry issued a revised framework to regulate sulphur dioxide (SO₂) emissions from thermal power plants. It has exempted many older coal-based plants from retrofitting Flue Gas Desulphurisation (FGD) devices and staggered deadlines for compliance based on location-based categorisation.
Relevance : GS 3(Environment and Ecology)
Scientific & Technical Basis
- SO₂: Harmful gas emitted during coal combustion; causes acid rain and respiratory illnesses.
- Also contributes to secondary pollutants like particulate matter.
- Ministry claims:
- Framework is evidence-based, informed by:
- Ambient SO₂ studies from 7 cities.
- Inputs from CPCB, NEERI, and IITs.
- Scientific analysis across 537 thermal power plants (TPPs).
- Framework is evidence-based, informed by:
Key Elements of the New Framework
| Category | Description | Deadline/Exemption |
| A | Within 10 km of Delhi-NCR or cities >1 million population | Compliance by Dec 2027 |
| B | Within 10 km of polluted cities (non-attainment) | Compliance case-by-case, based on expert review |
| C | Located outside polluted zones | Fully exempted from SO₂ retrofitting, must meet stack height norms |
- Plants retiring before Dec 2030 are also exempted, subject to ₹0.40/unit compensation if they continue operating beyond that date.
Cost Implications
- Retrofitting FGD systems across 537 plants estimated to cost ₹2.54 lakh crore.
Issues & Criticism
| Concerns | Explanation |
| “Regulatory dilution” | Environmental groups fear that exemptions weaken pollution control and delay India’s clean energy transition. |
| Health implications | SO₂ is linked to asthma, bronchitis, and cardiovascular issues. Exemptions may worsen local air quality. |
| Delayed action | India committed to SO₂ norms in 2015, but deadlines have been repeatedly extended. |
| Equity concern | Populations near Category B/C plants may still face localized pollution, yet plants may escape full compliance. |
Concept Check
| Term | Meaning |
| FGD (Flue Gas Desulphurisation) | A technology to remove SO₂ from exhaust flue gases of fossil-fuel power plants. |
| Non-attainment cities | Cities that consistently violate National Ambient Air Quality Standards (NAAQS). |
| Stack height norms | Chimneys must be tall enough to disperse pollutants and reduce ground-level concentration. |
Conclusion
The revised SO₂ compliance framework reflects a balancing act between health, environment, and economic costs. While phased deadlines reduce retrofitting burdens, critics warn of potential dilution of environmental safeguards.
