: Delhiites breathed in more polluted air on Friday, which was the beginning of round two of Odd-Even, than they did on Thursday, pointing towards the overpowering impact of meteorological factors.
The road-rationing scheme was meant to cut pollution by reducing the number of private petrol and diesel cars by half.
Friday did see less traffic on the roads due to the combination of the scheme and the holiday for Ram Navami.
But, harmful particulate matter in the air registered a hike.
According to the National Air Quality Index and the Union Ministry of Earth Science’s SAFAR index, levels of PM2.5 and PM10 were higher on Friday as compared to the last few days.
In fact, SAFAR had put the level of PM2.5 in the ‘good’ category on Thursday – a rare sight.
On Friday, the same SAFAR index had PM2.5 at 125.9 micrograms per cubic metre, putting it in the ‘very poor’ category as it was double the standard of 60. The level of PM10 was ‘poor’ at 273.6 micrograms per cubic metre, which was over two times the standard of 100.
Experts said this decrease was due to the fall in wind speed during the day.
As per the NAQI, Anand Vihar had an AQI score of ‘very poor’ at 352 and a maximum PM2.5 level of 500 micrograms per cubic metre. In all other monitoring stations for which AQI data was available, the air quality was ‘poor’.
Anumita Roychowdhury, who is the Centre for Science and Environment’s executive director and head of its clean air campaign, said air quality in the summer usually has “high variability”.
“The summer tends to have wide changes of weather. For instance, we had fast winds on Wednesday and Thursday that cleared the pollutants. But, Friday saw much slower wind,” said Ms. Roychowdhury.
She added that the impact of odd-even would only be visible after a week, as the changes in air quality within 24 hours are not enough to make observations.
Others added that there would be some impact of odd-even, though difficult to isolate from weather.
“The fact remains that the sources of pollution were reduced due to odd-even. That will have an impact. But, weather conditions could nullify that. We will have to wait and see,” said Sunil Dahiya, of Greenpeace.
