Context:

A recently released report from the Centre for Science and Environment (CSE) has highlighted a troubling increase in ground-level ozone pollution across urban India. 

More on the News: 

• The report titled Air Quality Tracker: An Invisible Threat reveals that cities like Delhi-NCR are experiencing alarming levels of ozone exceedances, posing significant health risks to residents.
• The researchers analyzed trends from April 1 to July 18 for the years 2020 to 2024, using granular, real-time data (15-minute averages) from the Central Pollution Control Board.

Key Highlights: 

   Ozone Pollution Trends in Major Cities: 

• The researchers analysed metropolitan areas of Bengaluru, Chennai, Kolkata, Mumbai and Pune. They also looked at the data for Delhi, Ahmedabad, Hyderabad, Jaipur and Lucknow.
• The study indicate that all cities monitored exceeded national ozone standards, with Delhi-NCR recording the highest number of exceedance days—176. 
• Other cities like Mumbai and Pune followed closely with 138 days, while Chennai had the fewest at just nine days.
• Notably, ozone levels were elevated even during nighttime, particularly in Mumbai, raising concerns about prolonged exposure to this harmful pollutant.

Health Implications of Ozone Exposure:

• Ground-level ozone is a highly reactive gas that can severely affect respiratory health, especially among children, the elderly, and individuals with pre-existing conditions like asthma.
• The report emphasizes that ozone can inflame airways, increase susceptibility to infections, and exacerbate chronic respiratory diseases, leading to more frequent hospitalizations.
• The 2020 State of Global Air report states that age-standardized rates of death attributable to ground-level ozone is among the highest in India

Ground Level Ozone: 

• Ground-level ozone is formed through complex interactions between nitrogen oxides (NOx) and volatile organic compounds (VOCs) when exposed to sunlight, rather than being directly emitted.
• The sources of NOx and VOCs include vehicles, power plants, factories, and natural emissions from plants.

Call for Regulatory Action:

• In light of these findings, researchers are urging stringent regulations to curb nitrogen oxide (NOx) emissions from vehicles and industries, which are precursors to ozone formation. 
• CSE calls for a multi-pollutant strategy under the National Clean Air Programme (NCAP) to effectively tackle the combined PM2.5 and ozone pollution threats. However, the programme currently focuses more on controlling PM 10 or coarse dust.
• The report stresses the need for improved monitoring and regulatory frameworks to address this growing public health crisis, as insufficient data and monitoring have hindered effective responses to ozone pollution in India.