India’s SO2 emissions up by 71 per cent in 5 years, shows US study

'CPCB underestimating pollution from coal-fired thermal power plants'

By Aparna Pallavi
Published: Monday 20 January 2014

Data released by NASA’s Aura satellite calls into question the veracity of Central Pollution Control Board’s (CPCB) claim made in 2012 that the mean sulphur dioxide (SO2) emissions in India decreased in 2010 as compared to 2001 level. A new study led by Zifeng Lu of Decision and Information Sciences Division of Argonne National Laboratory in Argonne, USA, based on images taken by the Aura satellite between 2005 and 2012, says that SO2 emissions from India’s thermal power plants has gone up by a whopping 71  per cent from what it was in 2005. The rapid rise in demand for power and the absence of regulations are seen as the reasons behind the drastic rise. The study was published online on December 5, 2013, in Environmental Science & Technology.

The study is based on a new technique for observing power plant emissions using measurements captured by the Ozone Monitoring Instrument (OMI) on the Aura satellite, developed by researchers two years ago. The OMI measures ozone and other key air-quality components (including sulfur dioxide and nitrogen dioxide) and collects data over the same locations at the same time daily. OMI data was used by researchers in a 2011 study to show that SO2 emissions from coal-fired power plants in the US had fallen in 2010 when compared to 2005 level. Images released with the study show rising emissions from coal-fired power plants in central India, especially the Vidarbha region of Maharashtra, Chhattisgarh and Jharkhand.

Image courtesy Environmental Science & Technology

CPCB's failure?    

In a press note released by NASA, lead author of the study, Lu, has said that the discrepancy between the figures in the study and those released by CPCB arise from the fact that CPCB’s figures are based on ground observation, and a large number of monitoring stations – 291 out of 361 in the country – are based in urban areas away from power plants, while just 70 stations collect measurements close to power plants. “We should know the air quality not only in populated cities, but also in industrial areas, where coal-fired power plants truly dominate national sulfur dioxide emissions,” Lu is quoted as saying. “On the one hand, local residents are influenced by these emissions, and on the other, long, lifetime, sulfur-containing air pollutants such as sulfate can be transported long distances to affect public health and the environment at a regional scale,” he said.

Images of SO2 emission patterns released along with the press note show that emission from smoke-stacks of power plants have risen between 2005 and 2012. In 2010, India surpassed the United States to become the world’s second highest emitter of SO2, second only to China.

The press note says that SO2 in small quantities is produced by volcanoes and other natural processes, but a substantial amount is produced by human activities such as the combustion of fuels with sulfur-containing impurities and the smelting of metals such as copper and nickel. The gas contributes to the formation of acid rain and, in high concentrations, can cause respiratory problems. It is also a precursor for sulfate aerosols, a type of suspended particle that can affect the properties of clouds—an effect that is difficult to measure and remains a large point of uncertainty in climate models.

Vidarbha's bane

The most important reason for rising SO2 emissions in central India’s power plants, says Suresh Chopane of the Chandrapur-based non-profit Green Planet Society (GPS), is antiquated technology. Chopane, who is a professor of environmental science at the Bhawanji Bhai Chavan College in Chandrapur district, has been agitating for the scrapping of the first two units of the Chandrapur Super Thermal Power Plant (CSTPS) for the last several years. “Many of the thermal power plants in Vidarbha, including CSTPS, and Koradi and Khaparkheda thermal power stations near Nagpur, have surpassed the 25-year limit of utility, and their pollution control systems are not working any more,” said he. “Respiratory illnesses have risen phenomenally in these areas. However, despite strong public demand, government is not shutting down these old and highly polluting units.”

He said that high SO2 and nitrogen dioxide emissions are causing acid rain in Chandrapur almost every year now for almost a decade.


Ozone monitoring instrument observations of interannual Increases in SO2 Emissions from Indian coal-fired power plants during 2005–2012

Ozone pollution in India due to power plant emissions

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