In short :
A high-powered committee led by Principal Scientific Advisor Ajay Sood has recommended scrapping the mandatory installation of Flue Gas Desulphurisation (FGD) units in most coal-based thermal power plants (TPPs), marking a major shift in India’s pollution control strategy
Background :
- FGD was mandated in 2015 under revised emission norms.
- Of India’s 600 TPP (Thermal Power Plants) units, only 8% have installed FGDs.
- Multiple deadline extensions (latest: Dec 31, 2024) have prevented penalties.
Major barriers:High cost, vendor shortage, tariff concerns, and COVID-19 delays.
FLUE GAS DESULPHURISATION
- Flue Gas Desulphurisation is a pollution-control technology used to remove sulphur dioxide (SO₂) from emissions of coal-fired power plants.
- It typically uses limestone/lime slurry, which reacts with SO₂ to form gypsum (used in construction).
- Meant to reduce acid rain, respiratory diseases, and environmental damage.
Committee Recommendation Highlights :
FGDs not needed nationwide; recommend selective use based on geography and pollution risk.
Reasons cited:
- Low ambient SO₂ levels in India (10–20 µg/m³ vs. 80 µg/m³ permissible limit).
- Low sulphur content in Indian coal.
- Negligible difference in SO₂ levels between plants with and without FGDs.
- Installing FGDs could increase CO₂ emissions by 69 million tonnes by 2030, defeating climate goals.
- FGDs unnecessary to meet National Ambient Air Quality (NAAQ) standards.
Proposed Classification :
Category A (Within 10 km of NCR/million-plus cities):
- 66 plants – must install FGDs by 2027.
- Only 14 have complied so far.
Category B (Near critically polluted/non-attainment cities):
- 72 plants – eligible for case-by-case exemptions.
Category C (All others):
- 462 plants – recommended for complete exemption.
Concerns Raised by Experts :
- India’s SO₂ emissions increased from 4,000 kt (2010) to 6,000 kt (2022)
- India imports coal from Indonesia, which emits less SO₂ despite a laxer standard (800 µg/m³ vs India’s 100 µg/m³).
- Scrapping FGDs may weaken long-term air quality enforcement, especially in high-emission zones.
SULPHUR DIOXIDE
Sulphur Dioxide is a colourless, reactive gas primarily produced by burning sulphur-containing fossil fuels like coal and oil. It is a major air pollutant, especially near industrial zones, and contributes to atmospheric corrosion, acid rain, and respiratory issues.
SOURCES of SO2 :
Major Source:
- Burning of fossil fuels in thermal power plants and industrial units.
Other Sources:
- Metal smelting and ore processing
- Volcanic eruptions
- Fuel-burning vehicles and machinery with high sulphur content
Contributes to Particulate Matter (PM) pollution and acid rain.
Related Topics for UPSC Linkage:
- Air Pollution and National Ambient Air Quality Standards (NAAQS)
- Particulate Matter (PM 2.5 & PM10)
- Fly Ash, Smog, CFCs, Lead, Ozone, CO, and SPM
- Environmental Impact Assessment (EIA)
- Air (Prevention and Control of Pollution) Act, 1981
UPSC Relevance :
GS3 – Environment, Pollution & Energy:
Environmental regulation vs. economic feasibility, India’s commitment to climate goals and clean energy transition, Debate around short-lived vs long-lived pollutants (SO₂ vs CO₂).
GS2 – Governance & Policy:
Role of expert committees in policy shifts, Inter-ministerial coordination between Environment and Power ministries.
Mains Practice Question:
“Do India’s ambient air quality conditions justify the exemption of Flue Gas Desulphurisation units in coal-based thermal power plants? Critically evaluate.”