The Central Pollution Control Board on Thursday told the National Green Tribunal there was no data to suggest the odd-even scheme had any impact on air quality and vehicular pollution, PTI reported. The board has been tracking air quality data since the second phase of the scheme was enforced on April 15. It said, “Fluctuations in PM10 and PM2.5 (particulate matter in the air) are due to the weather and change in wind patterns. Prima facie, there is no data to suggest the odd-even scheme has any impact on decrease in vehicular pollution.”

It will submit a detailed report to the NGT on May 2. In response, the NGT asked the Delhi government to start phasing out 15-year-old vehicles from the capital, an order it had passed earlier.

The Delhi government has aggressively promoted its odd-even scheme, which allows private cars with odd and even numbered license plates to ply only on alternate days. The Arvind Kejriwal-led government claimed its first phase of odd-even, implemented in January, reduced air toxicity by 15%. The state has also said it might consider making odd-even a monthly affair.

However, environmentalist Sunita Narain told The Times of India that the odd-even scheme is an emergency measure, and cannot be made a permanent move. She recommended permanent measures like boosting public transportation and implementing high parking charges, and said people would find ways to beat odd-even if it was made permanent in the capital.