SDG 3: Good Health & Well-being | SDG 11: Sustainable Cities & Communities
Institutions: Ministry of Environment, Forest & Climate Change
The Central Pollution Control Board (CPCB), in a reply filed before the National Green Tribunal (NGT) on 25 September 2025, stated that it had analysed ozone levels across 10 regions identified in the Centre for Science and Environment (CSE) report, covering 178 monitoring stations. Using the 2% exceedance criterion of National Ambient Air Quality Standards (NAAQS), CPCB confirmed that ground-level ozone breaches are significant in urban India.
This reply followed the CSE report released on 5 August 2024, which had warned of a “dangerous increase” in ozone pollution. On 21 March 2025, the NGT directed CPCB to examine the findings. In its reply (OA 1069/2024), CPCB reported that in 2023, 25 of 57 stations in Delhi NCR and 22 of 45 in Mumbai exceeded the 8-hour standard, while 4 stations each in NCR and the Mumbai Metropolitan Region also breached the 1-hour limit. These findings reinforce that ozone is emerging as a major pollutant alongside PM₂.₅ and NO₂, but requires different control strategies.
The CPCB’s submission highlights how civil society research (CSE), judicial oversight (NGT), and regulatory response (CPCB) intersect in India’s environmental governance. It underscores the need to expand the National Clean Air Programme (NCAP) beyond particulate matter, focusing also on NOx and VOC reductions from vehicles, industries, and solvents, airshed-based planning, and stronger real-time ozone monitoring. Addressing ozone also has co-benefits for health, agriculture, and climate.
What is Ground-Level Ozone? → A secondary pollutant formed when nitrogen oxides (NOx) and volatile organic compounds (VOCs) react under sunlight. Unlike PM₂.₅, it cannot be reduced by direct emission controls alone and is highly sensitive to meteorology.
What is CPCB? → The Central Pollution Control Board is India’s apex pollution regulator under the Ministry of Environment, Forest & Climate Change. It monitors air and water quality, sets standards, and enforces pollution control laws.
What is CSE? → The Centre for Science and Environment is a Delhi-based independent research and advocacy organisation. It publishes studies on environment, energy, climate, and public health that often inform policy debates.
What is NAAQS? → The National Ambient Air Quality Standards, set by CPCB under the Air Act, define permissible limits for pollutants such as PM₂.₅, NO₂, SO₂, and ozone. Exceedance of these norms triggers regulatory and legal action.
What is NGT? → The National Green Tribunal is a specialised judicial body set up in 2010 to handle environmental disputes. It has powers to enforce legal accountability on regulators and polluters, and to direct corrective measures.
Follow the full report here: www.greentribunal.gov.in