Centre defends SO2 norms tweak, says media reports misrepresent rationale behind move | Company Business News

New Delhi, Jul 14 (PTI) The government on Monday defended its recent move to ease sulphur dioxide (SO₂) emission norms for thermal power plants, saying the decision was based on detailed scientific studies and stakeholder consultations, and that media reports terming the move a “regulatory dilution” have “grossly misinterpreted” the notification.

In a statement issued a few days after the July 11 notification that extended deadlines and exempted a large number of coal plants from installing flue gas desulphurisation units, the ministry said, “The media reports misrepresent both the scientific evidence and the environmental policy rationale underlying the revised notification.”

It said the revised norms were framed after “extensive consultations with stakeholders and research institutions regarding the effectiveness and rationale behind stack emission standards for SO2 on 537 TPPs throughout the country, and its role in overall ambient air pollution of the region”.

“Further, the norms were based on detailed scientific studies which were carried out by premier institutions such as IIT Delhi, National Institute of Advanced Studies as well as by the National Environmental Engineering Research Institute (NEERI) — a constituent laboratory of Council of Scientific and Industrial Research (CSIR) besides scientific examination by Central Pollution Control Board,” it said.

Responding to criticism over the rollback of deadlines and exemptions for Category C plants, which make up the bulk of India’s coal fleet, the ministry said, “The media reports misrepresent both the scientific evidence and the environmental policy rationale underlying the revised notification.”

“Contrary to claims of regulatory dilution, the ministry’s decision represents a rational, evidence-based recalibration anchored in current ambient air quality data, sectoral emission trends and broader sustainability imperatives,” it said.

The ministry also rejected suggestions that the National Ambient Air Quality Standards (NAAQS) for SO2, last revised in 2009, are outdated.

“The contention that the existing SO2 NAAQS, last updated in 2009, are obsolete simply due to their age is scientifically unfounded,” it said.

“In fact, any revision to SO2 standards must be driven by its actual contribution to PM2.5 levels and its corresponding health burden, rather than rhetorical assertions,” the ministry added.

“Current exposure levels provide no credible evidence to suggest that SO2, under prevailing ambient conditions, is a major public health concern. Moreover, sulphate aerosols formed from SO2 constitute a relatively small fraction of PM2.5,” it said.

Quoting a study by IIT Delhi, the ministry said, “A detailed analysis carried out by IIT Delhi shows that sulfate contributes only 0.96 per cent to 5.21 per cent of PM2.5 and 0.57 per cent to 3.67 per cent of PM10 in cities near TPPs (thermal power plants).”

The ministry said the assertion that sulphur compounds contribute 12-30 per cent of PM2.5 is an unsubstantiated claim and not supported by any rigorous scientific studies conducted in major Indian cities and it significantly overstates the contribution of SO2 in India’s particulate pollution burden.

In the July 11 notification, the ministry said the compliance deadline for Category A plants, located within a 10-km radius of the National Capital Region or cities with a population of more than one million, remains December 2027.

Category B plants, situated within a 10-km radius of critically polluted areas or non-attainment cities, will now be assessed on a case-by-case basis instead of adhering to the earlier 2025 deadline.

Category C plants — all others not falling under Category A or B — have been completely exempted from the sulphur dioxide norms, provided they meet the prescribed stack height criteria by December 31, 2029. These plants were earlier required to comply by December 2026.

Of around 600 thermal power units in India, 462 are Category C units and 72 are Category B units.

India established stringent sulphur dioxide emission standards for coal-based power plants in December 2015, requiring compliance within two years.

Even after four extensions, 92 per cent of coal-fired power plants have not yet installed flue gas desulphurisation units to control SO2 emissions, a major air pollutant that converts into fine particulate matter (PM2.5) and causes a range of diseases.