Sulphur dioxide (SO₂) remains one of the most damaging air pollutants globally, with fossil-fuel combustion in power generation identified as its dominant anthropogenic source, driving acid rain, respiratory disease, and ecosystem degradation.
The combustion of sulphur-bearing coal in thermal power stations releases the largest share of anthropogenic SO₂ emissions. High-sulphur coal varieties, when burned without adequate flue-gas desulphurisation (FGD) technology, emit concentrated SO₂ plumes. In India, the power sector accounts for a disproportionately large fraction of national SO₂ output, a concern flagged repeatedly in environmental compliance reviews.
Smelting of non-ferrous metals such as copper, zinc, and lead, along with petroleum refining and cement manufacturing, constitute secondary industrial sources. Shipping and diesel transport also contribute, particularly in coastal and urban airsheds where heavy-fuel-oil combustion is prevalent.
SO₂ reacts atmospherically to form sulphate aerosols and sulphuric acid, causing acid rain that damages forests, freshwater bodies, and heritage structures. Epidemiological evidence links SO₂ exposure to aggravated asthma, bronchitis, and cardiovascular stress, imposing significant public health costs.
India's Environment (Protection) Act mandates emission standards for thermal power plants, with FGD retrofitting required for existing units. Globally, sulphur caps on marine fuels and clean-energy transitions are reducing SO₂ loads, though enforcement gaps and capital constraints slow compliance in developing economies.
Decarbonising the power sector and enforcing FGD mandates are the most direct levers to reduce SO₂ pollution. Balancing energy security with emission compliance demands time-bound regulatory frameworks backed by credible monitoring and financial support mechanisms.
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