Executive Summary:
The Ministry of Power addresses concerns regarding Sulphur Dioxide (SO2) emissions from coal/lignite-based Thermal Power Plants (TPPs) following a review of emission standards set in a 2015 notification. A 2025 notification outlines revised compliance timelines and categorizations for TPPs based on location and retirement plans, with differentiated SO2 emission standards. The policy emphasizes a balanced approach considering environmental impact, resource conservation, and economic factors, with a final compliance deadline of December 31, 2029, for stack height criteria.
Key Points / Main Content:
Emission Standards and Categorization:
* MoEFCC's 2015 notification on SO2 emission standards for coal/lignite-based TPPs was reviewed.
* TPPs are categorized as:
* Category A: Within 10 km of NCR or cities with a million-plus population.
* Category B: Within 10 km of Critically Polluted Areas or Non-attainment cities.
* Category C: All others.
* Flue Gas Desulphurization (FGD) systems are used to meet SO2 emission norms.
Revised Applicability of SO2 Emission Standards (Notification 11.07.2025):
* TPPs retiring before 31.12.2030 are exempt from SO2 emission standards if they submit an undertaking to CPCB and CEA.
* Existing and under-commissioning Category A TPPs must comply by 31.12.2027; new Category A plants after this date must comply before operation.
* Applicability for Category B plants will be decided by the Central Government based on recommendations from the Expert Appraisal Committee.
* Category C TPPs are exempt from SO2 emission standards if they comply with stack height criteria notified on 30.08.1990, with a compliance deadline of 31.12.2029.
General Requirements:
* All TPPs, regardless of SO2 emission standard applicability, must adhere to stack height criteria (30.08.1990).
* Non-compliant TPPs will face environmental compensation.
* FGD technology selection is based on cost-benefit analysis by the utility.
* The policy does not differentiate between coastal and non-coastal thermal plants.
Impact Analysis:
Thermal Power Plants (TPPs):
* Impact: TPPs must comply with revised SO2 emission standards and timelines based on categorization and retirement plans. Those not required to meet SO2 emission standards must still adhere to stack height criteria.
* Action Required: Determine category, implement FGD systems where applicable, adhere to compliance timelines, submit undertakings for retirement exemptions (if applicable), ensure compliance with stack height criteria, and conduct cost-benefit analysis for FGD technology selection.
Ministry of Environment, Forest and Climate Change (MoEFCC):
* Impact: Responsible for overseeing and enforcing the revised SO2 emission standards and stack height criteria.
* Action Required: Monitor TPP compliance, evaluate Expert Appraisal Committee recommendations for Category B plants, and enforce environmental compensation for non-compliant TPPs.
Central Pollution Control Board (CPCB) & Central Electricity Authority (CEA):
* Impact: Involved in the undertaking process for TPPs seeking retirement exemptions and in monitoring compliance.
* Action Required: Review and approve undertakings from TPPs seeking retirement exemptions.
Category B Expert Appraisal Committee for Thermal Power Projects:
* Impact: They will make key decisions on Category B plants, for the central government to then decide on.
* Action Required: Assess Category B plants and provide recommendations to the Central Government regarding the applicability of SO2 emission standards.
Consumers:
* Impact: Electricity prices may be affected due to the cost of implementing FGD systems.
* Action Required: No direct action required.
Key Entities Referenced
Flue Gas Desulphurisation FGD: A technology used to remove sulfur dioxide (SO2) from exhaust flue gases in coal-fired power plants.
Ministry of Environment, Forest and Climate Change MoEFCC: The Indian government ministry responsible for environmental protection and regulation, including setting emission standards for thermal power plants.
Sulphur Dioxide SO: A pollutant gas emitted from coal and lignite based Thermal Power Plants (TPPs), subject to emission standards.
Thermal Power Plants TPPs: Power plants that generate electricity by burning fossil fuels such as coal or lignite.
Central Pollution Control Board CPCB: A statutory organisation responsible for the prevention and control of pollution in India.
Central Electricity Authority CEA: A statutory body that advises the Indian government on policy matters and coordinates the development of the power sector.
Principal Scientific Adviser PSA: The chief advisor to the Government of India on scientific matters.
National Capital Region: The metropolitan region which encompasses the Union Territory of Delhi and surrounding districts from adjacent states.
GOVERNMENT OF INDIA
MINISTRY OF POWER
LOK SABHA
UNSTARRED QUESTION NO.4602
ANSWERED ON 21.08.2025
MITIGATION OF SULPHUR DIOXIDE EMISSIONS
4602. SHRI MADDILA GURUMOORTHY:
Will the Minister of POWER
be pleased to state:
(a) whether the Government has accepted the recent recommendation of the
committee led by the Principal Scientific Adviser to withdraw the mandatory
installation of Flue Gas Desulphurisation (FGD) units in all coal-fired thermal
power plants and if so, the reasons for this rollback despite its risks on health
and environment;
(b) whether any alternative technologies or regulatory frameworks have been
proposed to replace FGD systems in controlling SO₂ emissions from thermal
power plants and if so, the details thereof; and
(c) whether the Government is considering a differential policy for coastal and
non-coastal thermal plants based on their access to cheaper alternatives like
seawater-based FGD treatment and if so, the details thereof?
A N S W E R
THE MINISTER OF STATE IN THE MINISTRY OF POWER
(SHRI SHRIPAD NAIK)
(a) to (c): Ministry of Environment, Forest and Climate Change (MoEF&CC)
notified emission standards [including Sulphur Dioxide (SO )] for coal / lignite
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based Thermal Power Plants (TPPs) vide its Notification dated 07.12.2015.
Further, MoEF&CC vide Notification dated 31.03.2021 prescribed for
categorization of TPPs into the following 03 categories for compliance of emission
standards:
(i) Category-A (Within 10 km radius of National Capital Region or cities having
million plus population);
(ii) Category-B (Within 10 km radius of Critically Polluted Areas or Non-attainment
cities);
…..2.- 2 -
(iii) Category- C (Other than those included in Category A and B).
To meet the SO emission norms, Flue Gas Desulphurization (FGD) system is
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being installed in coal/lignite based TPPs.
The SO emission standards prescribed in MoEF&CC Notification dated
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07.12.2015 have been reviewed by the Central Government taking into
consideration the various representations received regarding exemption or
relaxation in timelines of these 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 SO
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concentration in ambient air and heavy burden on consumers due to increase in
electricity price etc.
Besides, the scientific studies conducted by independent research
institutions regarding effectiveness & rationale behind these standards and its
role in overall ambient air pollution of the region were also considered to evaluate
the need of universal applicability and enforcement of these standards.
Various Stakeholders’ consultation meetings among MoEF&CC, Ministry of
Power (MoP), Central Pollution Control Board (CPCB), O/o Principal Scientific
Adviser (PSA) to the Government of India, Central Electricity Authority (CEA),
Research Institutions were also held in the matter. The recommendations of the
stakeholders’ consultation meetings, including the meeting chaired by the PSA to
Govt. of India, was also taken into consideration by MoEF&CC.
In view of above, MoEF&CC has issued a Notification on 11.07.2025 regarding
applicability of SO emission standards along with timelines for compliance by
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TPPs and its details are given below:
(i) TPPS declared to retire before 31.12.2030 shall not be required to
meet specified standards for SO emissions in case such plants
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submit an undertaking to Central Pollution Control Board (CPCB) and
Central Electricity Authority (CEA) for exemption on ground of
retirement of such plant;
(ii) the existing and under commissioning Category A TPPs shall comply
with SO emission standards by 31.12.2027. Other Category A plants
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to be commissioned after 31.12.2027 will operate only after ensuring
compliance of these standards;
……3.- 3 -
(iii) for all Category B Plants or Units, whether existing or upcoming, the
applicability of SO emission standards, shall be decided by the
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Central Government based upon recommendations of the Expert
Appraisal Committee in charge of Thermal Power Projects as per the
procedure laid in the Notification dated 11.07.2025;
(iv) the SO emission standards shall not be applicable to all Category-C
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TPPs subject to compliance of stack height criteria notified by
MoEF&CC on 30.08.1990 and timeline for compliance of stack height
criteria is 31.12.2029.
The category wise applicability of SO emission standards in TPPs have
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been decided based on detailed scientific studies and analysis of ambient SO
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concentrations across the country, including areas near TPPs. This approach
applies the precautionary principle for controlling and abating air pollution in
densely populated and other air pollution sensitive areas, while also emphasizing
on resource conservation by avoiding additional consumption of water, auxiliary
power, and limestone, and avoiding the increase in carbon footprint/CO2
emissions resulting from the operation of deployed control measures, as well as
mining and transportation of limestone required for these measures.
In all cases where SO emission standards are not applicable, all such TPPs
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(irrespective of location) shall ensure compliance to stack height criteria notified
by MoEF&CC on 30.08.1990 governing SO emissions from TPPs to aid proper
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dispersion of pollutants and mitigate environmental impacts.
Further, TPPs are required to comply with emission standards within the
prescribed time limits, failing which environmental compensation will be levied
on the non-compliant TPPs.
The selection of technology for FGD installation is decided on the basis of
cost benefit analysis by the utility. The policy regarding FGD installation is
irrespective of coastal and non-coastal thermal plants.
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