NEW DELHI: The air quality in Delhi-NCR was more toxic this summer in comparison with the previous year as the city experienced high ozone levels with many stations exceeding the safe mark, Centre for Science and Environment (CSE) reveals in its latest study.
The report points out that while the higher number of hot days usually pushes ozone levels beyond the safe limit, the spread of stations this summer is much wider. On average, 16 stations in Delhi-NCR exceeded the standard daily in March-April — a 33% rise from the previous year — with New Delhi and south Delhi being the worst affected.
Of the six big metros in the country, ozone levels were the highest in Delhi, followed by Mumbai, Kolkata, Hyderabad, Chennai, and Bengaluru.
“Even before we could control the problem of particulate pollution, the toxic threat of ground-level ozone is catching up. Despite the warning signs, this problem has not attracted adequate policy or public attention. Inadequate monitoring, limited data and inappropriate methods of trend analysis have weakened the understanding of this growing toxic risk,” said Anumita Roychowdhury, executive director of research and advocacy at CSE, adding that it could lead to a serious health crisis. According to the 2020 State of Global Air report, age-standardised rates of death attributable to ozone are among the highest in India.
This year’s early onslaught of heatwaves initiated the spatial spread of ground-level ozone in March itself, with April being the worst. “Dr K S shooting range in south Delhi is the most chronically affected area in Delhi-NCR. It has exceeded the standard for 85 days this March-May, followed by JLN Stadium, RK Puram and Nehru Nagar,” the report states.
Greater Noida is the major hotspot outside Delhi, while Faridabad has the least instances in the region, it points out, adding that east and central Delhi are facing a worsening trend, with Patparganj seeing the highest increase in days — 68 — compared with the past three years’ average.
According to the report, the practice to average out the data of all stations to determine AQI doesn’t indicate the severity or the exposure.
A difficult pollutant to track, the ground-level ambient ozone is not directly emitted from any source but is formed when complex reactions between pollutants emitted from various combustion sources react in sunlight. “Those with respiratory conditions, asthma, chronic obstructive pulmonary disease, and particularly children with premature lungs and older adults, are at serious risk,” the report states.
