Anti-polluting system exemption to thermal plants based on proof: govt  -OxBig News Network

Days after it was criticised for exempting a large section of the thermal power plants from installing flue gas desulphurisation (FGD) systems, which cut sulphur dioxide emissions, the Union Environment Ministry said its decision represented a “rational and evidence-based recalibration”.

The total installed capacity of coal-based thermal power plants in India is approximately 210,969 MW. The coal-based capacity is a significant portion of India’s overall power generation capacity, contributing to over 45% of the total.  Sulphur dioxide emissions are linked to air pollution.

Citing studies from institutions such as IIT-Delhi, National Institute of Advanced Studies as well as by the National Environmental Engineering Research Institute (NEERI), the environment ministry said current exposure levels provided no credible evidence to suggest that sulphur dioxide, under prevailing ambient conditions, is a major public health concern.

A detailed analysis carried out by IIT-Delhi shows that sulfate contributes only 0.96 per cent to 5.21 per cent of particulate matter (PM2.5) and 0.57 per cent to 3.67 per cent of PM10 in cities near thermal power plants. The institute in the study found no significant difference in sulphur dioxide levels between cities with thermal power plants equipped with operational FGDs and those without them.

A study by NEERI also suggested that sulphur dioxide emissions contribute minimally to overall ambient air pollution levels in the form of particulate matter.

There are 180 operational thermal power plants in India and these have 537 units. As per government’s official statement in August 2024, only 34 have installed FGD. Now, only about 11 per cent of India’s 537 thermal power plant units have to mandatorily install FGD systems.

With the notification of new regulations, those plants, called ‘Category A’ ( located within 10 km radius of the National Capital Region) will have to install FGD. For cities which are beyond the NCR region, an expert committee of the government will take a call if the plants located within 10 km radius of the polluted areas should install FGD.

In December 2015, the environment ministry implemented emission norms for sulphur dioxide and nitrogen dioxide and mandated the installation of FGD by 2017. In 2017, the NGT rapped the ministry for delaying the compliance. In 2024, the ministry gave an extension to the thermal power plants for installing the FGD.

Congress leader Jairam Ramesh said sulphur dioxide is a health hazard and pointed out, “The NAAQS were last updated in 2009, when the prevailing levels of particulate matter and emissions were of a decidedly lower order of magnitude, and when the catastrophic public health consequences of particulate matter were not known. A revision of the NAAQS therefore is long due. In the absence of such a revision, the ministry’s policymaking will continue to be driven by flawed metrics.”

The ministry claimed that contention that the existing sulphur dioxide National Ambient Air Quality Standard (NAAQS) last updated in 2009, are obsolete simply due to their age is scientifically unfounded. 

Contrary to claims of regulatory dilution, the ministry’s decision represents a rational, evidence-based recalibration anchored in current ambient air quality data, sectoral emission trends, and broader sustainability imperatives. The contention that the existing sulphur dioxide NAAQS last updated in 2009, are obsolete simply due to their age is scientifically unfounded,” the ministry said.