The Union Environment Ministry has extended the deadline for coal-fired power plants to meet sulphur dioxide emission norms introduced in 2015, while fully exempting several plants near critically polluted areas. The directive issued on Saturday states that only 66 plants, classified as ‘Category A’, must now adhere to the standards. The remaining 72 plants, classified as ‘Category B’, will be evaluated on a case-by-case basis. Over 450 plants, classified.
As Category C’, are exempt from meeting SO₂ emission norms but will still meet stack height criteria and timelines prescribed by the Central Pollution Control Board (CPCB). The order follows recommendations made by a high-level committee chaired by Principal Scientific Adviser Ajay Kumar Sodo. The government has also recommended a relaxation in timelines and focusing on controlling particulate matter and installing electrostatic precipitators for FGD installation.
India has revised its sulphur dioxide (SO₂) emission standards for coal‑based thermal power plants once more. This move, announced in mid‑July 2025, significantly relaxes the earlier 2015 mandate requiring universal installation of flue gas desulphurisation (FGD) systems. Below is a deeper look at the revision, its rationale, responses, and implications. (Coal)
major urban
A government notification issued on July 11, 2025, exempts nearly 79% of coal plants—those located beyond 10 km of cities with populations over one million—from installing FGDs. Plants within 10 km of major urban areas (Category A, about 10%) must comply by December 2027, while those in proximity to critically polluted or “non‑attainment” zones (Category B, ~11%) will face SO₂ norms only on a case‑by‑case basis. Category C facilities, covering most locations outside urban centres, are granted full exemption, provided they meet mandatory stack‑height norms.
Indian coal
The Environment Ministry has defended the relaxation as a data‑driven, pragmatic recalibration. Studies from IIT Delhi, NEERI, NIAS, and the CPCB indicate that ambient SO₂ levels across Indian cities typically range between 3 and 20 µg/m³, far below the national standard of 80 µg/m³. Indian coal is naturally low in sulphur (<0.5%), stack heights promote effective dispersion, and converting SO₂ reductions into significant health gains is limited. In contrast, installing FGDs would cost an estimated ₹2.4–2.5 lakh crore and increase CO₂ emissions due to added power demand and limestone transport.
environmental clearance
- Category A plants: Must install FGDs by end‑2027; new units post‑2027 must meet norms before operation.
- Category B plants: Compliance will depend on reviews conducted via the PARIVESH portal, with deadlines extending to 2028 depending on status.
- Category C plants: Fully exempt but must meet stack-height requirements by December 2029.
Plants planning to retire before December 2030 may formally opt out; otherwise, they face a compensation fee of ₹0.40 per unit for continued operations beyond that date.
Environmental group
Proponents argue the policy reduces the cost burden on consumers by avoiding electricity price increases of ₹0.25–₹0.30 per unit and avoiding ancillary CO₂ emissions. Critics counter that the long‑term health costs, lost productivity, and environmental damage may far outweigh short‑term savings. They also highlight the risk of undermining prior investments, such as the billions already spent by NTPC and other firms on FGD system.
The revised SO₂ norms illustrate a tension between environmental regulation and economic pragmatism. While the government frames the move as evidence‑based targeting, critics say it undermines India’s clean‑air goals and climate commitments. The selective enforcement model may ease costs in the short run—but could weaken regulatory consistency in the long term. Vigilance from regulatory authorities and continued monitoring of ambient air quality and health outcomes will be essential going forward.
q1. What change has been made to SO₂ norms for coal plants?
The government has relaxed sulphur dioxide emission rules, exempting most coal plants from installing flue-gas desulfurization (FGD) systems.
q2. How many power plants are now exempt?
Around 78% of India’s coal and lignite plants are fully exempt from SO₂ compliance requirements.
q3. What are the new plant categories under the revised norms?
Plants are grouped into Categories A, B, and C based on proximity to cities or polluted zones, with only Category A strictly required to comply by 2027.
q4. Why were the norms relaxed?
The government cites low ambient SO₂ levels, high costs of FGD installation, and limited air quality benefits as reasons.
q5. What are the concerns raised by critics?
Environmental experts warn of increased health risks, reduced accountability, and weakened enforcement of clean air goals.
