RTI finds CPCB lacks full emission data for coal-based power plants near Delhi-NCR

Amid severe winter pollution in Delhi-NCR becoming a major cause for concern for officials and residents alike, a new Right to Information (RTI) reply revealed that the Central Pollution Control Board (CPCB) had not conducted full stack-emission monitoring for any coal-based thermal power plants (TPP), except two, within a 300-km radius of the capital in the past decade. These plants are among the region’s key sources of sulphur dioxide (SO2) and fine particulate matter.

Full stack-emission monitoring refers to the direct, on-site measurement of pollutants coming out of the chimney (stack) of an industrial plant, such as a thermal power plant. It is the most accurate method to measure what a plant is actually releasing into the air.

The RTI response shows that the CPCB has conducted full stack-emission monitoring for just two thermal power plant within a 300-km radius of Delhi, despite the emission standards notified on December 7, 2015.

The two plants—the Deenbandhu Chhotu Ram Thermal Power Plant in Haryana and the Guru Hargobind Thermal Power Plant in Punjab—were partially monitored, the RTI revealed. The CPCB’s reply states that complete monitoring, analysis and final results for these two plants are still awaited.

The Ministry of Environment, Forest and Climate Change (MoEF&CC) issued a notification on July 11, 2025, making sulphur dioxide (SO2) emission standards compulsory for Category A thermal power plants. These are larger plants with a higher pollution potential.

Within 300 kilometres of Delhi, there are four such plants. Three of them—NTPC Dadri in Uttar Pradesh, Mahatma Gandhi Thermal Power Station in Haryana and Indira Gandhi STPS in Haryana—have installed flue-gas desulphurisation (FGD) systems. An FGD system removes SO2 from the plant’s emissions before smoke is released into the air.

“No data exists on whether these three power plants are meeting SO2 emission standards,” said environmental activist Amit Gupta, who filed the RTI.

The fourth plant, Panipat Thermal Power Station, has not installed this pollution-control system yet. The government has given it more time, extending its deadline to December 31, 2027.

There are a total of 12 coal-based thermal power plants within 300 kilometres of Delhi.

Estimates by the Centre for Research on Energy and Clean Air (CREA) show that these plants released about 281 kilo-tonnes of sulphur dioxide (SO2) between June 2022 and May 2023.

CREA has said that installing flue-gas desulphurisation (FGD) systems could cut SO2 emissions in the NCR from 281 kilo-tonnes to around 93 kilo-tonnes, a reduction of roughly 67 per cent.

Gupta said the absence of complete stack monitoring directly affects the ability to track pollution from TPPs.

“The RTI reply makes it clear that Delhi-NCR’s pollution crisis is not just about weather or vehicles, it is also about a complete lack of enforcement,” he said. “The CPCB has not conducted full stack-emission monitoring for any thermal power plant within 300 kilometres of Delhi, despite having 10 years to implement the 2015 standards,” he added.

Stack monitoring measures SO2, nitrogen oxides (NOx), PM 2.5, fly ash and heavy metals directly at the chimney. Without this data, regulators cannot verify compliance or identify excessive emissions.

Gupta said that without scientific measurements, plants can continue operating polluting units unchecked, contributing to secondary PM 2.5 formation that thickens winter smog.