Context:
A government-appointed expert committee led by Principal Scientific Advisor Ajay Sood has recommended rolling back India’s 2015 policy mandating the installation of Flue Gas Desulphurisation (FGD) units in all coal-fired thermal power plants (TPPs). The recommendation comes amid high installation costs, sluggish compliance, and mounting power demand.
What Is an FGD Unit?
FGD units are designed to remove sulphur dioxide (SO₂) from flue gas produced during coal combustion. SO₂ is a key contributor to respiratory illness and air pollution.
There are three major types of FGD systems:
- Dry sorbent injection – Injects powdered limestone into flue gas
- Wet limestone treatment – Passes flue gas through limestone slurry, producing gypsum
- Seawater scrubbing – Uses coastal seawater to absorb and neutralize SO₂
Why SO₂ Emissions Matter
- SO₂ causes acid rain, respiratory ailments, and contributes to secondary PM2.5 formation
- Studies show 15% of India’s PM2.5 is linked to coal burning, with SO₂ accounting for 80% of that share
- Reducing SO₂ is vital to improving ambient air quality and public health
Implementation Status in India
- The 2015 mandate required all 537 coal-based TPPs to install FGD units
- Only 39 plants had complied as of April 2025
- Original 2018 deadline extended multiple times — latest compliance dates stretch to 2029
- In December 2024, the Ministry of Environment extended deadlines by another 3 years, citing no official reason
Is There an Alternative to FGD Units?
- Experts affirm that no current alternative exists to remove SO₂ at source from coal combustion
- Reducing reliance on coal or investing in cleaner energy alternatives is a long-term solution, but FGDs remain essential in the interim
