Ozone levels perilously high in Delhi's residential areas: Report

NEW DELHI: Prominent residential areas of the Capital, including Patparganj, RK Puram and Nehru Nagar, as well as some industrial areas and low-income areas of Najafgarh and Sonia Vihar are among the places most severely affected by high levels of ozone gas, which has reached dangerous levels in the Capital.

Delhi and its neighbouring cities of Faridabad and Gurgaon of are witnessing "substantial ozone build-up" from February to May, the Centre for Science and Environment (CSE) on Friday claimed, cautioning that these are early signs of a "dangerous trend".

The CSE said it has analysed real-time air quality data available from 31 automatic monitoring stations of the Delhi Pollution Control Committee (DPCC), the Central Pollution Control Board (CPCB) and the India Meteorological Department (IMD) for February-May.

"This shows a progressive increase in ozone pollution, with the onset of summer. Several densely-populated areas have shown a high frequency of days violating the ozone standards. With high pollution and temperature levels, and growing heat stress, the formation of ozone has accelerated and is frequently exceeding the standards," the CSE said in a statement.

According to the analysis, at least on 23 days, ozone emerged as the "dominant pollutant" along with particulate matter in the daily air quality index. "These are early signs of a dangerous trend," the green body said.

It also claimed that green areas on the outskirts of Delhi were "most vulnerable".

Ozone is formed in polluted areas and some of that escapes with the wind to cleaner environments. It builds up there because it has no opportunity to further react with other pollutants to dissipate, as it happens in polluted areas in a cyclical process, the CSE said.

"The Dr Karni Singh Shooting Range near the Asola Sanctuary (in south Delhi) has recorded the highest number of days exceeding the ozone standards," the analysis said.

The posh Lutyens' Delhi area and prime places in central Delhi were also affected, it said. The analysis stated that air quality monitoring in Jawaharlal Nehru Stadium, near Lodhi Road CGO Complex, and Major Dhyan Chand National Stadium, near Delhi High Court, has shown that the number of days with levels exceeding the standards were "47 percent and 22 percent of all days" during the entire period, respectively.

Micro-mapping of ozone levels across the city, done to understand the vulnerable areas, showed that there were some locations where over "50 per cent" of the days during February-May, ozone levels exceeded the standards.