Context

• The Ministry of Environment, Forest and Climate Change (MoEFCC) has exempted nearly 78% of India’s thermal power plants (TPPs) from installing Flue Gas Desulphurisation (FGD) systems.

About Fuel Gas Desulphurisation 

• FGD systems are technologies used in coal-based thermal power plants to remove SO₂ from exhaust flue gases before they are released into the atmosphere.
• Mechanism: The most common FGD method involves using a wet scrubber that reacts with a limestone slurry to convert SO₂ into gypsum.
• Purpose: Helps reduce acid rain, secondary particulate matter, and improves ambient air quality.

Sulphur Dioxide: A significant Air Pollutant

• Sulphur dioxide (SO₂) is a major air pollutant primarily released from coal-fired power plants and other fossil fuel combustion.
• It poses serious health and environmental risks. As a respiratory irritant, SO₂ can trigger asthma, bronchitis, and other lung diseases.
• It is also a precursor to PM2.5, fine particulate matter linked to heart attacks, strokes, and premature death.

Categorisation of Thermal Power Plants

• Category A: Comprises ~11% of India’s 600 TPP units and has to mandatorily install FGD systems by December 30, 2027.
• These are located within 10 km radius of the National Capital Region or are cities with a population of at least a million (2011 Census). 
• Category B: Comprises another 11% of TPP units and are located near Critically Polluted Areas (CPAs) or Non-Attainment Cities (NACs).
• Installation of FGD is subject to approval by the Expert Appraisal Committee (EAC).
• Deadline: December 30, 2028, if required.
• Category C:  It comprises the remaining 78% of TPP units. They are fully exempted from installing FGD systems and are mostly located in regions outside pollution hotspots.

Rationale Behind Policy Shift

• According to the Ministry, India’s ambient SO₂ levels have been declining, with 2023 measurements across 492 cities showing compliance in all but two.
• Indian coal naturally has low sulphur content, leading to relatively lower SO₂ emissions.
• Studies have found no major difference in SO₂ concentrations between cities with and without FGD-fitted plants.

Concerns

• Health Impacts: SO₂ is a precursor to PM2.5, which can penetrate lungs and bloodstream. Chronic exposure is linked to asthma, heart disease, and premature death.
• According to the Lancet Commission on Pollution and Health 2022, pollution-related deaths in India exceeded 2.3 million annually.
• Violation of Polluter Pays Principle: Exempting TPPs from installing FGDs violates the environmental principle that polluters should bear the cost of pollution mitigation.
• Undermines Pollution Targets:  India’s Clean Air Programme and COP26 commitments are weakened by this decision.
• Air Pollution Dispersion: Coal plants emit pollutants that travel up to 200 km from the source.
• Tall chimneys do not eliminate pollution but disperse it into wider areas, impacting rural populations and neighboring states.

Way Ahead

• Health-Cost Internalisation: Use models like the Health Impact Assessment (HIA) to account for medical costs, productivity loss, and mortality.
• Accelerate Renewable Energy Transition: Shift focus towards cleaner sources like solar, wind, and biomass to reduce dependency on coal.
• Pollution Control Mandates for All Categories: Pollution is not limited by administrative categories; hence, uniform emission norms should be enforced.
• Build FGD Installation Capacity: Encourage Make in India initiatives to build indigenous capacity for FGD manufacturing and deployment.
• Public Disclosure and Monitoring: Real-time emissions data of SO₂, PM2.5, and other pollutants should be made publicly available for accountability.