Syllabus: 

GS3: Conservation, Environmental Pollution and Degradation, Environmental Impact Assessment.

Context: 

Recently, the Central Scientific Committee recommended that Sulphur-cleaning devices in coal plants are not necessary. 

More on the News:

• India’s annual SO2 emissions has risen from 4,000 kilotonnes in 2010 to 6,000 kilotonnes in 2022. 
• A high-level panel of experts, led by the Principal Scientific Advisor, has recommended that India needs to scrap its decade-old policy requiring all coal-fired thermal power plants (TPPs) to install Flue Gas Desulphurisation (FGD) units.
• Although 92% of India’s 600 thermal power plants are yet to install FGD units, the new recommendation would exempt nearly 80% of them from the requirement to do so.

Flue Gas Desulphurisation (FGD): 

• Flue Gas Desulphurisation (FGD) is a process used to remove Sulphur dioxide (SO2) from flue gas, which is the exhaust gas produced by burning fossil fuels like coal, oil, or natural gas. It helps reduce acid rain, improve air quality, and protect public health. 
• They are crucial for meeting environmental regulations and mitigating the harmful effects of SO2 emissions. 
• The FGD units are required to be retrofitted in thermal power plants to cut harmful sulphur dioxide (SO2) emissions. 

Key Findings of the Committee:

• The verdict draws on three reports by the CSIR-NEERI, the National Institute of Advanced Studies, and the Indian Institute of Technology, Delhi. 

• The guiding principles informing the committee’s recommendation are that: 

• SO2 levels in ambient air across the country are around 10-20 micrograms/cubic meter, well below India’s air quality norms of 80.
• Since Indian coal is low in sulphur, and also studies show that sulphur dioxide (SO₂) concentrations in cities near thermal plants with FGD units are not significantly different from those without them — with all readings remaining well within permissible limits.

• The committee found concerns about sulphates – a potential by-product when SO2 emissions reach certain atmospheric levels, thus forming particulate matter (PM). 

• They cited nationwide data showing low elemental sulphur levels (max 8 µg/m³), making PM reduction via FGDs insignificant.

• The report also argues that installing FGDs in all TPPs could worsen global warming by adding around 69 million tons of CO₂ (2025–30) due to higher power consumption, while only reducing 17 million tons of short-lived SO₂ — a trade-off deemed unjustified given India's low-sulphur coal.

Key Recommendations of the Committee:

The committee recommends a tiered approach:

Category A: 

• TPPs within 10 km of the National Capital Region or cities with populations over one million should install FGDs.
• There are 66 such plants, and only 14 of them have installed FGDs. Currently, all these plants are required to comply by 2027.

Category B: 

• TPPs near critically polluted or non-attainment cities may be considered for exemptions on a case-by-case basis.
• There are 72 such plants, with only four having installed FGD. These plants currently have a deadline of 2028.

Category C: 

• The remaining TPPs, especially older units, could be exempted from the FGD mandate.
• The remaining 462 plants all come under Category C, of which 32 have installed FGDs. 
• These plants have been given a 2029 deadline, but the committee has now recommended that Category C plants be exempted completely.