A study conducted by the Indian Institute of Technology (IIT) Kharagpur has found that there has been a significant drop in sulphur dioxide (SO2) levels in India in the last decade as compared to the previous three decades.

A report in the KPG Chronicle, which is the official news platform of IIT Kharagpur, states that the reduction in emission and concentration of SO2 has been due to environmental regulation and the adoption of effective control technologies such as ‘scrubber’ and ‘flue gas desulphurization’, according to the study conducted by a team of researchers from the Centre for Oceans, Rivers, Atmosphere and Land Sciences (CORAL) of the institute.

Sulphur dioxide (SO2) is one of the criteria pollutants that mainly released from the coal-based thermal power plants. At higher concentrations, it has hazardous effects on public health and environs.

The study represents temporal changes in SO2 concentrations across India in the last four decades (1980-2020), according to the report. Thermal power plants (51%), and manufacturing and construction industries (29%) are the main sources of anthropogenic SO2 in India.

The temporal analyses reveal that SO2 concentrations in India increased between 1980 and 2010 due to high coal burning and lack of novel technology to contain the emissions during that period.

Both economic growth and air pollution control can be performed hand-in-hand by adopting new technology to reduce SO2 and GHG emissions.

“SO2 is an atmospheric pollutant and can be converted to sulfate aerosols in high humid conditions. These aerosols can affect cloud reflectively, rainfall and regional climate by modifying the radiative forcing.

At high concentrations, SO2 affects adversely on human health and ecosystem as well. Therefore, continuous monitoring of its abundance in the atmosphere is highly warranted, as these kind of analyses would help making the policy decisions related to emissions.

This particular study is serving that purpose,” remarked Jayanarayanan Kuttippurath, from CORAL and lead author of the study, in the KGP report.

An improved air quality monitoring network is needed to understand the spatial and temporal changes of pollutants, which would help to make policies relevant to improve air quality and to meet targeted reduction in emissions.

The measurements and emissions in this study have uncertainties and are not computed in absolute figures. However, the trends computed are statistically significant across all Indian regions.

Therefore, the findings have important implications for future environmental policies on India’s SO2 emissions and for understanding the impact of SO2 on regional climate, air quality, ecosystem dynamics, and public health.

This study also provides a baseline for future studies that would critically examine changes in SO2 pollution as a result of the country’s socio-economic development.

“Our analysis shows Indo-Gangetic Plain and Central and Eastern India regions as the SO2 hotspots in India. Although there is a relative reduction in SO2 in the last decade, the concentration of SO2 is still very high in these regions. Therefore, we need to continue our efforts to reduce SO2 emission in India, whether it is with innovative technology or environmental regulations,” Vikas Kumar Patel, another author of the paper, said, as quoted in the report.

The report also highlights the remarks made by Prof. V K Tewari, Director, IIT Kharagpur, “India relies heavily on coal-based thermal power plants to meet its energy demands. Analysis of spatial and temporal changes in SO2 using accurate and continuous observations is required to formulate mitigation strategies to curb the increasing air pollution in India. Since 2010, India’s renewable energy production has also increased substantially when India adopted a sustainable development policy.

The shift in energy production from conventional coal to renewable sources, solid environmental regulation, better inventory, and effective technology would help to curb SO2 pollution in India.

India’s nationally determined contributions under the Paris Agreement includes achieving about 40% cumulative electric power installed capacity from non-fossil fuel-based energy resources by 2030. This commitment would help to reduce the dependency on the coal-based energy, and also help to curb the SO2 pollution in the future.”

Due to rapid industrialization and urbanization in the past decades, India’s energy demand has been increased substantially with coal consumptions. The expansion of coal-based electricity generation in India is the primary cause of the country’s high emissions.

Currently, India is one of the world largest emitters of SO2, accounting for more than 15% of global anthropogenic emissions. On the other hand, India’s power sector has seen an increase in renewable energy capacity, which would help to curb the pollution in India, the report states.