The National Green Tribunal (NGT) has taken note of an alarming rise in ground-level ozone pollution across major Indian cities, citing a recent report submitted by the Central Pollution Control Board (CPCB). The CPCB’s analysis, which covered 10 regions, highlighted the severe impact on India’s two largest metropolitan areas.
The CPCB’s recent affidavit noted that the elevated ozone levels are primarily linked to intense photochemical reactions in the presence of sunlight and heat, with major precursor pollutants originating from human activity.
Data:
The CPCB analysis used a 2% exceedance criterion of the National Ambient Air Quality Standards (NAAQS) for the 8-hour ozone concentration:
- Delhi-NCR: 25 out of 57 monitoring stations exceeded the safe limit.
- Mumbai Metropolitan Region (MMR): 22 out of 45 monitoring stations exceeded the safe limit.
The analysis of one-hour standards showed that four stations in each of the NCR and MMR breached the limit in 2023.
NGT action:
The tribunal noted that the high ground-level ozone concentrations are largely attributable to the following sources:
- Emissions from the transport sector.
- Emissions from power plants and industrial activities.
The CPCB statement, as recorded in the NGT order, confirmed the regional disparity. It said, “The Delhi-NCR and Mumbai Metropolitan Region reported higher exceedances of ozone concentration compared with other regions.”
In response, the NGT has directed the Union Ministry of Environment, Forest and Climate Change (MoEF&CC) to form an expert committee to study the health impacts and recommend specific control measures for ozone and its precursors. The matter is scheduled for further hearing on November 12, 2025.
