Centre extends SO2 norm compliance deadlines for thermal power plants
This is not the first time that ministry of environment, forest and climate change (MoEFCC) has extended the timelines for thermal power plants to comply with SO2 norms
New Delhi: The union environment ministry has issued a notification once again extending the timelines for thermal power plants to comply with sulphur dioxide (SO2) emission standards. According to expert analysis, the notification also effectively exempts a large proportion of thermal power plants—representing more than 75% of India’s thermal power capacity—from complying with SO2 norms, provided they ensure compliance with stack height regulations.
Addressing SO2 emissions is critical due to their contribution to secondary particulate emissions. The new notification, issued on July 11, introduces a revised compliance mechanism for SO2 norms applicable to coal- and lignite-based thermal power plants. It categorises these plants into three groups:
Category A: Located within a 10 km radius of the National Capital Region (NCR) or cities with a population exceeding one million.
Category B: Located within a 10 km radius of Critically Polluted Areas (CPAs) or Non-Attainment Cities.
Category C: All other plants not included in Categories A or B.
Overall, if a thermal power plant plans to retire before December 31, 2030, it is not required to meet the SO2 emission standards, provided it officially submits an undertaking to the Central Pollution Control Board (CPCB) and Central Electricity Authority (CEA), stating that the plant will be retired by December 31, 2030.
All existing and under-construction category A plants must meet SO2 norms by the end of 2027.
{{/usCountry}}All existing and under-construction category A plants must meet SO2 norms by the end of 2027.
{{/usCountry}}For category B plants, the Centre will determine whether SO2 standards will apply. Existing plants that have already received environmental clearance can now apply for a review of the applicability of SO2 norms. This application must be submitted on the PARIVESH portal within six months of the notification date.
{{/usCountry}}For category B plants, the Centre will determine whether SO2 standards will apply. Existing plants that have already received environmental clearance can now apply for a review of the applicability of SO2 norms. This application must be submitted on the PARIVESH portal within six months of the notification date.
{{/usCountry}}Category C thermal power plants are now exempted from SO3 emission standards. Instead, they must comply with stack height requirements as per an earlier notification issued in 1990. All existing category C thermal power plants must ensure compliance with the stack height rule by December 31, 2029.
{{/usCountry}}Category C thermal power plants are now exempted from SO3 emission standards. Instead, they must comply with stack height requirements as per an earlier notification issued in 1990. All existing category C thermal power plants must ensure compliance with the stack height rule by December 31, 2029.
{{/usCountry}}“Exempting all category C plants from SO3 norms simply based on location ignores cumulative pollution, especially in areas like Singrauli or Korba which are not ‘officially’ CPAs but are severely impacted. Notably, more than 75% of India’s thermal power capacity—amounting to approximately 166,885.5 MW—falls under category C. Granting such a large-scale exemption undermines the effectiveness of the emission standards and poses a serious risk to public health and environmental sustainability,” a statement issued by Centre for Science and Environment on Saturday said.
{{/usCountry}}“Exempting all category C plants from SO3 norms simply based on location ignores cumulative pollution, especially in areas like Singrauli or Korba which are not ‘officially’ CPAs but are severely impacted. Notably, more than 75% of India’s thermal power capacity—amounting to approximately 166,885.5 MW—falls under category C. Granting such a large-scale exemption undermines the effectiveness of the emission standards and poses a serious risk to public health and environmental sustainability,” a statement issued by Centre for Science and Environment on Saturday said.
{{/usCountry}}This is not the first time that the ministry of environment, forest and climate change (MoEFCC) has extended the timelines for thermal power plants to comply with SO2 norms. HT reported on September 7, 2022, that the environment ministry extended the deadline to meet SO2 norms to December 31, 2027, for units scheduled to retire, and to December 31, 2026, for plants that will continue operations beyond that period. The ministry had already given prior extensions to coal-fired power plants for meeting SO2 and other pollution norms.
Again, through an order dated December 30, 2024, the MoEFCC further extended the compliance timelines for SO2 emissions to December 2027, December 2028, and December 2029 for category A, B, and C thermal power plants, respectively.
Addressing SO2 emissions is critical due to their role in the formation of secondary particulate matter 2.5 (PM2.5), a major air pollutant identified by scientists as a significant health hazard.
Sulphur dioxide emission standards were first notified by the centre in 2015 and have been amended periodically since.
“Many representations were received regarding exemption or relaxation in timelines of these emission standards due to limited availability of technology providers, its techno-economic feasibility, negative impact of COVID-19 pandemic on supply chain, price escalation due to high demand and low supplies, low SO2 concentration in ambient air and heavy burden on consumer due to increase in electricity prices etc., and explicit recommendation of the Ministry of Power was received in this regard,” a notification issued on July 11 said.
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The notification also said that several studies were conducted by research institutions to assess the effectiveness and rationale behind the SO2 standards and their impact on regional ambient air pollution. Stakeholder consultations were held with industry, the ministry of power, CPCB, scientific institutions, and others.
It further states that a committee under the CPCB was constituted to assess the issue holistically. The committee reviewed study reports, relevant data, and implementation challenges before making its recommendations.
“CPCB, after detailed analysis, has submitted its recommendation based on its study on National Ambient Air Quality Standards of Sulphur dioxide across most of the regions of the country; resource conservation in terms of avoiding additional consumption of water, auxiliary power, and limestone; increase in carbon footprint or Carbon dioxide emission into the atmosphere due to operation of control measures being deployed, and mining and transportation of limestone required for these control measures; the techno-economic feasibility of implementation of such control measures in all coal or lignite based thermal power plants…” the notification added.
Meeting SO2 norms requires the installation of Flue Gas Desulphurisation (FGD) systems, which remove sulphur compounds from fossil fuel emissions. Minister of state for power Shripad Naik had said, in response to a Rajya Sabha question last year, that no SO2 norms were applicable until the end of 2015, and hence, FGD system manufacturing capacity was almost non-existent in the country. “FGD technology being new to our country, there are at present limited vendors with limited capacity to supply and install FGD components,” Naik said.
“Coal-based power generation is one of the biggest contributors to air pollution after transportation, primarily due to sulphate formation from SO2 emissions. However, repeated delays in implementing emission standards for coal-based power plants since 2017 have hindered progress toward cleaner air. Exempting category C plants, which account for nearly 80% of India’s installed power capacity, from SO2 controls will severely undermine efforts to achieve clean air across the country,”Envirocatalysts founder and lead analyst Sunil Dahiya.
