An analysis of the odd-even scheme by Centre for Science and Environment showed that air pollution in Delhi dropped during the first few days but suddenly increased from April 22.
The second phase of the odd-even car rationing scheme helped "reduce" the air pollution during the initial few days but farm and forest fires played spoilsport and it registered a "sudden spike" from April 22 onwards, a green body said today.
An analysis of the scheme by Centre for Science and Environment (CSE) showed that air pollution dropped during the first few days but suddenly increased from April 22.
"Analysis of NASA satellite pictures has exposed massive crop fires in Punjab and Haryana that started around April 19, which could be the reason behind the rise in pollution levels," the body said.
It said the benefit of the scheme was "misinterpreted" due to crop fires that led to a sudden spike in pollution around a week after its start.
"Our investigation has exposed that irresponsible explanation of the air quality trend has led to misinterpretation of the benefit of the odd-even scheme and helped create the industry myth that vehicles are not the problem.
"They have missed the massive crop fires that started around April 20 and got intense over time and elevated pollution not only in Delhi, but in other cities of northern India as well," CSE said.
It said that PM2.5 levels declined substantially compared to the previous fortnight between April 15 and April 23.
The average PM2.5 level during the first nine days was 24 per cent lower than the average of the previous fortnight.