Air pollution reduced during the first 10 days of the second phase of odd-even, but fires in Uttarakhand, Punjab and Haryana hit Delhi’s air quality after April 21, the Centre for Science and Environment said on Tuesday.
In its analysis of the 15-day scheme, the CSE found that the level of fine particulate matter, PM2.5, between April 15 and April 23 declined compared to the previous fortnight. The first nine days of odd-even, which started on April 15, saw PM2.5 levels 24 per cent less than the average of the previous fortnight.
After April 22, the CSE said, there was a spike in pollution. On April 23, the PM2.5 level went up by 92 per cent and the level of nitrogen dioxide spiked by 47 per cent. Delhi wasn’t the only city affected – the air quality index in Faridabad, Agra and Lucknow in Uttar Pradesh saw PM2.5 levels increase after April 26.
Sunita Narain, director-general of CSE, said the reason for the sudden spike in pollution was the crop fires in Punjab and Haryana from April 21. Using NASA satellite images, the CSE was able to find that there were “virtually no crop fires” in Punjab and Haryana before odd-even started and in the first few days of the scheme.
Starting April 21, the fires erupted and became more intense from April 23 onwards. The worst was April 26. Levels of pollution in Delhi increased despite an increase in wind speed during the period of the fires.
“There was a decrease in pollution in Delhi during the first 10 days of odd-even, but the forest fires in Uttarakhand and the crop fires in Punjab and Haryana hit air quality after that,” said Ms. Narain.
She added that recent media reports that odd-even had not worked, and that pollution had gone up were irresponsible.
“The half-baked interpretation of data has led automobile companies to claim that odd-even did not work, so vehicles weren’t the problem. But that is misrepresenting the facts and over-simplifying,” said Ms. Narain.
