Air Quality Debate: Eased Sulfur Emissions from Thermal Power Plants Cause Contention
In a move that has raised eyebrows among environmental experts, the Ministry of Environment and Forests (MoEF) has exempted most coal-based thermal power plants from installing Flue Gas Desulphurisation (FGD) systems. This decision affects about 78-80% of the plants, with the majority of them located outside sensitive zones or categorised as Category C plants.
The rationale behind this decision includes cost savings, local ambient SO2 levels, and energy/climate impacts. Installing FGDs involves high capital expenditure, and the exemption is estimated to save up to Rs 1,16,000 crore in capital costs overall, plus Rs 24,000 crore annually in tariff expenses, reducing electricity costs by Rs 0.22 per unit.
However, the decision has raised concerns about adverse health and environmental consequences due to continued sulphur emissions in many regions. SO2 reacts in the atmosphere to form ammonium sulfate, a major component of fine particulate matter (PM2.5), which is linked to serious health problems including asthma, bronchitis, heart attacks, and other respiratory diseases.
The exemption risks maintaining or increasing SO2 emissions, thereby undermining air quality and public health, especially near exempted plants. Critics argue that the modest increase in CO2 emissions from FGDs is a worthwhile trade-off for reducing SO2 and PM2.5, and that the government’s approach sacrifices long-term health and productivity for short-term cost savings.
It is important to note that coal-fired power is harmful to health and the environment. Coal burning releases a range of pollutants, including sulphur dioxide, nitrogen oxides, and mercury, which contribute to acid rain, smog, and climate change.
The remaining TPPs, called Category C, which account for over 75% of coal-fired power capacity, are exempt from treating sulphur emissions. For plants that are within 10 km of critically polluted areas or 'non-attainment cities' (Category B), sulphur emissions will be considered on a 'case-by-case basis'.
The Centre has reasoned that ambient SO2 concentration in 10 cities were well below hazardous levels. However, the 2015 policy was based on the assumption that SO2 emissions are linked to hazardous PM 2.5 emissions. Other technologies, such as dry sorbent injection, were virtually excluded in favour of FGD.
Regulations on using coal with no more than 34% ash content were relaxed in 2020, presuming that FGD would address this aspect. However, the Centre has noted that the flue gas desulphurisation equipment to reduce sulphur emissions is not a viable option due to extra coal consumption and expected carbon emissions.
As a result, there does not seem to be a regulation to curb ash content or sulphur emissions at present. This decision has sparked concern among experts and the general public, who are calling for stricter regulations to protect public health and the environment.
Published on August 4, 2025.
[1] Environmental Pollution Control Authority (EPCA) [2] Central Pollution Control Board (CPCB) [3] Centre for Science and Environment (CSE) [4] Power Ministry [5] Ministry of Environment and Forests (MoEF)
- The exemption of most coal-based thermal power plants from installing Flue Gas Desulphurisation (FGD) systems by the Ministry of Environment and Forests (MoEF) has been met with criticism from environmental experts.
- The decision to exempt these plants is based on cost savings, local ambient SO2 levels, and energy/climate impacts, but critics argue that it risks maintaining or increasing SO2 emissions.
- The continued sulphur emissions could have adverse health and environmental consequences, as SO2 reacts in the atmosphere to form ammonium sulfate, a major component of fine particulate matter (PM2.5), linked to various health problems.
- The Centre has reasoned that ambient SO2 concentration in 10 cities were well below hazardous levels, but the 2015 policy assumed that SO2 emissions are linked to hazardous PM 2.5 emissions.
- The remaining plants, called Category C, which account for over 75% of coal-fired power capacity, are exempt from treating sulphur emissions, but plants within 10 km of critically polluted areas will be considered on a 'case-by-case basis'.
- Despite the relaxation of regulations on coal with no more than 34% ash content in 2020, assuming that FGD would address this aspect, the Centre has noted that the flue gas desulphurisation equipment to reduce sulphur emissions is not a viable option due to extra coal consumption and expected carbon emissions.
- Stricter regulations are being called for by experts and the general public to protect public health and the environment, citing the harmful effects of coal-fired power on health and the environment, which includes the release of sulphur dioxide, nitrogen oxides, and mercury, contributing to acid rain, smog, and climate change.
