New Delhi: Air pollutant concentrations increased significantly on April 15, the day Delhi government's 'odd-even' scheme started, a green body on Saturday said as it underlined the need for more stringent measures to control air pollution in the city.
"PM10 (particles with diameter less than 10 micrometer) and PM2.5 (particles with diameter less than 2.5 micrometer) concentrations have increased significantly at most places in Delhi and NCR during the last few days due to reduction in wind speeds.
"The concentrations are 1.6-3.6 times above the standard of PM2.5," The Energy and Resources Institute (TERI) said.
It said that a few days ago, the pollutant concentrations dropped below the standards due to higher wind speed and enhanced vertical thermal diffusion leading to better dispersion of pollutants.
"However, now the concentrations have increased again and are significantly violating the standards at most places in Delhi and NCR," TERI said.
It said that the background monitoring station in upwind of Delhi near Bahadurgarh town shows PM2.5 concentrations of 132 ug/m3 , depicting significant contributions of upwind areas in Delhi's air quality and wind, which is predominantly blowing from North-west direction, carries pollutants towards the city of Delhi.
It said that the downwind stations in NCR towns like Noida, Ghaziabad and Gurgaon show PM2.5 levels of 123,140, 113 ug/m3, respectively, which are "even higher" than some locations in Delhi.
TERI said that other than PM, gaseous pollutants like NO2 also violated the limits in Delhi at Punjabi Bagh, Anand Vihar and R K Puram.
"Delhi needs stringent measures for control of air quality. Odd-even is only one of these initiatives, many more interventions need to be made at the NCR scale and across different sectors for effective control of air pollution," it said.
TERI has been carrying out a trend analysis of the three main pollutants PM10, PM2.5 and NO2 at nine locations - Mandir Marg, R K Puram, Punjabi Bagh, Anand Vihar, Bahadurgarh, Lodhi Road, Ghaziabad, Gurgaon and Noida.
The objective is to analyse the effect of odd-even scheme on air pollutant concentrations in different parts of the city and the exercise will continue till April 30, it said.