New Delhi: A new report by the Centre for Science and Environment says that the ongoing air pollution in Delhi-NCR is being worsened by the intransigence of thermal power plants, most of which are not complying with emission control norms.

"Delhi and NCR cannot meet the clean air benchmark and protect public health if the continuous sources of pollution like thermal power plants remain high emitters. These plants have not been able to meet the standards and are at varying stages of progress simply because the target dates for compliance are shifting continually,” says Anumita Roychowdhury, Executive Director, Research and Advocacy, CSE.

Delhi-NCR has 11 thermal power plants. The CSE analysis focuses on particulate matter, nitrogen oxide and sulphur dioxide emissions by these coal-based thermal power plants. The analysis is based on the environmental status reports of these plants accessed from the website of Central Electricity Authority, a technical arm of the Union Ministry of Power, from April 2022 to August 2023.

The Union Ministry of Environment, Forest and Climate Change introduced strict emission norms for coal-based power plants in December 2015 -- to be complied with within two years. Since then, the norms have been diluted for several parameters and deadlines have been repeatedly delayed.

On the lapse of the first deadline of December 2017, a 5-year extension was granted to all power plants except the ones in Delhi-NCR. Because of high levels of pollution in the region, the plants in NCR were tasked to comply by 2019. Except for the Dadri TPP and the Mahatma Gandhi TPP, all the plants in NCR failed to meet the revised deadline and continued to operate in violation of the norms till another extension of the deadline was given in March 2021. At this time, the ministry classified all power plants, including the ones in NCR, under three different categories -- A, B and C -- based on the criteria defined by the Central Pollution Control Board.

Based on the new criteria, except for four plants – the Dadri, Indira Gandhi, Mahatma Gandhi and Panipat TPPs – the remaining seven plants were placed under category C, giving them more time to comply with the norms. Because of these extensions in the deadline, Panipat TPP remains the only plant that is unlikely to meet the emission norms by the compliance deadline.

However, says Nivit Yadav, Programme Director of industrial Pollution at CSE, “this does not imply that the emissions from other plants are anywhere within the prescribed limits, as we see in our current analysis.”

Almost eight years after the introduction of the notification on emission norms, and six years after the first deadline, three plants in the NCR - Harduaganj thermal power station of UPRVUNL, Panipat Thermal Power Plant of HPGCL, and Guru Hargobind TPP of PSPCL— are still reporting very high suspended particulate matter emissions, finds the CSE report.

“Minor changes in operational parameters and regular maintenance of electrostatic precipitators can make a substantial improvement in compliance of power plants where SPM norms are not being met continuously”, says Yadav.

Nitrogen oxide norms have already been relaxed by the government: nearly all the plants should be able to meet these norms with proper operational intelligence and with the assistance of the original equipment manufacturers to carry out necessary modifications in the plant boilers, point out CSE researchers.

Despite the relaxation in norms and deadlines, four plants – Panipat TPS, Rajiv Gandhi TPP, Yamunanagar TPP in Haryana and Guru Hargobind TPP in Punjab - have exceeded the NOx norms several times during the reporting period.

In the case of sulphur dioxide, the Mahatma Gandhi TPP is the only power plant in NCR where the norms are within the prescribed limit. Dadri TPP is another plant that has sulphur dioxide control equipment in place, but the plant has reported high SO2 readings 86 per cent of the time during the reporting period – the reason could be either FGDs not in service or of inadequate capacity, or very high sulphur content of the coal being used.

All the coal power plants in NCR have reported SO2 emissions up to three times over the prescribed limits.

“SO2 is a reactive gas and converts to sulphates in the form of fine particulate matter - PM2.5 - which poses an even greater risk to health and environment. Therefore, control of SO2 is crucial from the perspective of controlling particulate matter emissions,” adds Dr DD Basu, Former Director of CPCB.