A working group will be formed by the Central Pollution Control Commission (CPCB) to “classify thermal power plants (TPP) into three categories according to their location,” said the ministry in the notification dated April 1.

In addition, TPP units in “non-compliant cities” and those located within 10 kilometers of severely polluted areas must meet emission standards by December 31, 2023.

Non-compliant cities are those that have consistently failed to meet national ambient air quality standards. The CPCB has identified 124 of these cities.

Coal-fired power plants in the rest of the areas must meet the new standards by December 31, 2024, according to the notification.

TPPs declared retired before December 31, 2025, are “not required to comply with the specified standards in the event that these plants submit a commitment to the CPCB and the CEA (Central Electricity Authority) exemption on grounds of retirement “, the notification states.

The Ministry of the Environment revised the emission standards for particulate matter (PM), sulfur dioxide and nitrogen oxides for TPPs in December 2015, requiring them to install emission control systems by now. December 2017.

The deadline has been extended to December 2022 for all power plants in the country due to issues and implementation challenges. However, power plants in the National Capital Region were expected to meet revised standards by December 2019.

Earlier this year, the Department of Energy asked the Department of the Environment to extend the deadline for meeting emission standards for all thermal power plants from 2022 to 2024, citing a delay due to various reasons, including coronavirus pandemic and import restrictions.

The main pollutants from coal-fired power plants are nitrogen oxides (NOx), sulfur dioxide (SO2) and particulate matter (PM).

According to the Center for Science and the Environment (CST), PPTs account for over 60 percent of the total emissions particles; 45 percent SO2; 30 percent NOx; and over 80 percent mercury, in the country.

These are also responsible for 70 percent of total freshwater withdrawal by all industries, according to an analysis by the Green Think Tank.

A recent CSE compliance report showed that of the 12 power plants located around Delhi, SO2 control technology was only available at two plants.