Recent changes by India’s Environment Ministry exempt most coal-based thermal power plants from installing flue gas desulphurisation (FGD) devices. These devices reduce sulphur dioxide (SO2), a harmful pollutant linked to serious health and environmental issues. Plants near Delhi-NCR must comply by December 2027, while others face case-by-case decisions. This marks a shift from earlier strict mandates aiming to curb SO2 emissions by 2017, which were repeatedly extended.
Significance of Sulphur Dioxide Emissions
SO2 is a major air pollutant emitted from burning coal in thermal plants. It reacts in the atmosphere to form fine particulate matter (PM2.5), responsible for one-third of India’s PM2.5 pollution. PM2.5 penetrates deep into lungs causing asthma, bronchitis, heart attacks, and premature death. SO2 also causes acid rain, damaging ecosystems and crops.
Government’s Past Measures on SO2 Control
In 2015, India introduced emission norms requiring FGD devices by 2017. Thermal plants delayed compliance citing high costs, power disruptions, and rising electricity bills. Deadlines were extended multiple times. In 2021, plants were classified into three categories based on location and pollution risk, with staggered compliance dates between 2022 and 2024.
Latest Norms and Exemptions
The 2025 revision exempts about 78% of plants (Category C) from installing FGD devices. Category A plants near Delhi-NCR must comply by 2027. Category B plants near critically polluted areas face case-by-case decisions. Plants retiring before 2030 may seek exemption after submitting an undertaking.
Rationale Behind the Revised Norms
The government based its decision on studies by IIT Delhi, NIAS, and NEERI. These studies claim SO2 levels near plants are within national ambient air quality standards. They argue that FGD devices increase carbon dioxide and particulate pollution. The focus, they suggest, should shift to overall particulate matter reduction rather than SO2 alone.
Criticism and Concerns from Experts
Experts contest government claims, arguing monitoring stations do not capture the full impact of SO2 emissions. SO2 converts into PM2.5 over long distances and days, worsening air quality far from the source. Independent research marks that power plant emissions remain contributor to air pollution and health risks. Critics warn that relaxing SO2 controls may undermine air quality improvements.
Impact on Public Health and Environment
SO2 exposure causes respiratory irritation and long-term cardiovascular risks. The formation of secondary pollutants like PM2.5 exacerbates health hazards. Acid rain from SO2 harms forests, soils, and water bodies. Addressing emissions from coal plants is vital for India’s air quality and environmental sustainability.
Questions for UPSC:
- Discuss the impact of coal-based thermal power plants on air quality and public health in India. How effective are emission control technologies like flue gas desulphurisation devices?
- Critically examine the challenges in implementing environmental regulations in India’s power sector. What policy measures can balance energy needs and pollution control?
- Explain the formation and effects of fine particulate matter (PM2.5) in the atmosphere. With suitable examples, discuss the role of secondary pollutants in air pollution.
- Comment on the significance of air quality monitoring systems in managing pollution. How can data limitations affect policy decisions and public health outcomes?
