Kiran Raj

The National Green Tribunal (NGT), Principal Bench, New Delhi, chaired by Justice Prakash Shrivastava and Dr. A. Senthil Vel, Expert Member, has addressed the alarming issue of elevated ground-level ozone concentrations in Delhi. Registered as Original Application No. 605/2024, the matter arose from suo motu cognizance of a news report detailing repeated breaches of permissible ozone levels in the national capital.

The tribunal's order dated December 23, 2024, outlined findings from the Delhi Pollution Control Committee (DPCC), which documented ozone concentrations exceeding the prescribed national limit of 100 micrograms per cubic meter over an eight-hour period. Notably, Nehru Nagar recorded 224.9 micrograms per cubic meter, followed by Patparganj with 188.3 micrograms and RK Puram with 175.4 micrograms. Such exceedances were observed in areas with high vehicular activity and dense populations.

In compliance with earlier directives, the Central Pollution Control Board (CPCB) submitted a report dated December 20, 2024. The report attributed the rise in ozone levels to precursors such as nitrous oxides (NOx), volatile organic compounds (VOCs), methane, and carbon monoxide (CO). It noted that controlling ozone requires regional and national interventions due to the transport of ozone and its precursors across geographic boundaries.

The CPCB referenced the National Clean Air Programme (NCAP), initiated in 2019, which includes city-specific clean air action plans implemented in 130 identified non-attainment cities. Measures under these plans aim to curb emissions from key sectors, including:

• Transitioning to BS VI-compliant vehicles and cleaner fuel standards to mitigate vehicular emissions.

• Promoting electric mobility through the PM E-DRIVE scheme and the establishment of charging infrastructure.

• Adopting ethanol blending in fuels and implementing vehicle scrappage policies to remove outdated and polluting vehicles.

• Enforcing stricter industrial emission standards and incorporating biomass co-firing in power plants to reduce emissions.

The report also highlighted sectoral measures to address biomass burning, particularly paddy straw burning in northern India. These include financial incentives for biomass management facilities, stricter enforcement actions during peak agricultural seasons, and frameworks for promoting alternative straw management practices.

The CPCB recommended a comprehensive study involving air quality experts to investigate elevated ozone levels in Delhi. This study would assess transboundary, biogenic, and anthropogenic sources of ozone and propose region-specific mitigation strategies. The tribunal, acknowledging the necessity of this study, remarked that its findings could aid in addressing the issue systematically.

In its directive, the tribunal ordered the impleadment of the Union Ministry of Environment, Forest, and Climate Change (MoEF&CC) as a respondent. The ministry was instructed to file an affidavit responding to the CPCB’s recommendations. “Let notice be issued for filing the response by way of affidavit, especially commenting upon the recommendations made by the CPCB,” the Bench stated.

Additionally, the tribunal required the CPCB to submit a fresh report detailing the implementation of the Centre's existing measures. The matter has been listed for further proceedings on April 21, 2025.

Case Title: "Oh-zone! Why this prominent pollutant in Delhi air is becoming a cause for concern"
Case Number: Original Application No. 605/2024
Bench: Justice Prakash Shrivastava, Chairperson, and Dr. A. Senthil Vel, Expert Member

[View/Download order]