India’s Sulphur Dioxide Emission Norms
India recently extended the deadline for coal-fired power plants to install flue gas desulphurisation (FGD) units. This move relaxes sulphur dioxide (SO2) emission control norms. The extension has drawn criticism from independent researchers who warn of serious health and environmental risks. Despite strict norms set in 2015, most plants have not complied. The debate continues over the scientific basis and public health impact of this delay.
SO2 Emission Norms
In 2015, India introduced stringent SO2 emission standards for coal-based power plants. These required installation of FGD units within two years to reduce SO2 emissions. SO2 is a harmful pollutant that converts into fine particulate matter (PM2.5), causing respiratory and cardiovascular diseases. Even with multiple deadline extensions, over 90% of plants have failed to install FGDs.
Recent Policy Changes and Exemptions
Recently, the environment ministry extended the compliance deadline from December 2024 to December 2027 for plants near large cities and the National Capital Region. Plants in less polluted areas were exempted if they met stack height criteria. The ministry justified this citing several studies, techno-economic issues, COVID delays and recommendations from the Ministry of Power.
Scientific Criticism of Policy Relaxation
The Centre for Research on Energy and Clean Air (CREA) challenged the ministry’s reasoning. It argued that studies from institutions like NEERI, NIAS and IIT Delhi are being selectively interpreted to delay FGD installation. CREA brought into light that ambient SO2 measurements do not reflect actual emissions or their conversion into PM2.5. SO2 norms are based on stack emissions, not ambient air readings. Using low ambient SO2 levels to avoid FGDs is misleading and scientifically incorrect.
Impact of FGDs on Air Quality
Research shows FGDs can reduce ambient particulate matter by 10-20% near power plants. IIT Delhi’s studies found reductions in sulfate aerosols up to 200 km away from plants after FGD installation. Despite this, some recent reports recommend halting FGD rollout, narrowing study scopes to limited cities. CREA warns such selective focus undermines broader evidence of FGDs’ benefits.
Health and Environmental Concerns
Coal-fired power plants caused tens of thousands of premature deaths annually in recent years. The health burden is expected to rise with planned capacity expansions of 80-100 GW. Although FGDs slightly increase CO2 emissions, this rise is marginal compared to emissions from new coal plants. Delays in FGD installation risk worsening air quality and public health.
Operational and Economic Arguments
Claims that FGDs cause prolonged power plant shutdowns are disputed. Data from NTPC shows most FGDs were installed during scheduled maintenance without extra downtime. NTPC has already installed FGDs in plants with 20 GW capacity and is working on 47 GW more. The economic concerns cited by policymakers are challenged by evidence of feasible large-scale FGD deployment.
National and Cross-Boundary Pollution Effects
Coal power plants contribute to India’s PM2.5 pollution, especially in winter and urban areas. Their emissions affect air quality far beyond local regions. This pollution is comparable to that from the vehicle sector, where strict emission controls were implemented earlier. FGDs are essential to reduce this cross-boundary pollution and protect public health nationwide.
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