The Union Environment Ministry has once again extended the deadline for coal-fired power plants to meet sulphur dioxide (SO₂) emission norms introduced in 2015, while fully exempting several plants located near critically polluted areas from compliance.

As per the latest directive issued on Saturday, of the approximately 600 coal-based plants originally required to install flue-gas desulphurisation (FGD) systems to curb SO₂ emissions, only 66 located within a 10-kilometre radius of Delhi-NCR or cities with populations exceeding one million (as per the 2011 Census) must now adhere to the standards. These plants, classified as ‘Category A’, have a new compliance deadline of 31 December 2027.

Meanwhile, 72 plants identified as ‘Category B’—those within a 10-kilometre radius of critically polluted areas or cities not meeting national air quality standards—will be evaluated on a case-by-case basis for SO₂ norm applicability.

Over 450 plants classified as ‘Category C’, which are located outside Delhi-NCR and beyond any critically polluted zones, have been completely exempted from meeting the SO₂ emission norms. However, these plants will still be required to meet stack height criteria and timelines prescribed by the Central Pollution Control Board (CPCB).

This marks the fifth time the government has deferred the deadline for SO₂ emission compliance since the norms were first introduced in 2015. The exemption from installing FGD systems is significant, as the technology is designed to reduce SO₂ emissions, which contribute to the formation of fine particulate matter capable of entering the human bloodstream and causing severe health risks.

The Environment Ministry’s latest order follows recommendations made by a high-level committee chaired by Principal Scientific Adviser Ajay Kumar Sood. The committee concluded that FGD technology is not essential for all coal-based plants. Supporting this view, a report by the National Institute of Advanced Studies highlighted that Indian coal, which fuels around 92 per cent of the country’s thermal power generation, has low sulphur content. The report argued that widespread FGD installation would increase auxiliary power consumption and long-lived carbon dioxide emissions, despite reducing short-lived SO₂ emissions.

The CPCB also conducted detailed assessments of ambient SO₂ levels and recommended limited FGD installations, noting that current pollution control efforts were inadvertently increasing CO₂ emissions and expanding the environmental footprint due to the use and transportation of limestone.

Additionally, the Ministry of Power had explicitly recommended a relaxation in timelines following consultations with industry bodies, CPCB, scientific institutions, and other stakeholders. The government stated that instead of universal FGD deployment, efforts should focus on controlling particulate matter and installing electrostatic precipitators.

Previously, the government had identified 537 coal-based units with a total capacity exceeding 200 Gigawatts (GW) for FGD installation. As of March, only 49 units (25 GW) had FGD systems installed. Contracts had been awarded for 211 units (90 GW), while 180 units (58 GW) were in the tendering phase and 97 units (27 GW) were under pre-tendering, according to official data presented in the Lok Sabha.