The CPCB also pointed out that emission from different sources, apart from vehicular pollution, also varied, making it difficult to analyse the scientific benefits of the scheme.
In a report to the National Green Tribunal (NGT) on pollution levels before and during the second round of the odd-even scheme, the Central Pollution Control Board (CPCB) said it has found an “increase in the concentration of pollutants at most monitoring locations during the scheme”.
The submission comes in response to a plea filed by petitioner Vardhaman Kaushik concerning air pollution in Delhi-NCR.
The Delhi Pollution Control Committee (DPCC) and the CPCB were directed by the NGT to submit a status report on the odd-even scheme. The NGT is expected to take up the issue Tuesday.
The CPCB’s analysis, submitted to the NGT Friday, collected data on pollutants including PM 10, PM 2.5, Sulphur dioxide (SO2), Benzene, Ozone (O3), Nitrogen dioxide (NO2) and Carbon monoxide (CO) in the fortnight before the scheme (April 1-14) and during the scheme (April 15-30).
In its report, the CPCB noted that based on data collected from seven stations, “the decrease in vehicular emission was not a dominant enough factor to impact observed data”.
CPCB scientists said air quality was affected by various meteorological factors such as wind speed, temperature, solar radiation, humidity and “mixed height of pollutants”.
“These factors come into play, besides emission from various sources. The fortnight before the scheme, prominent wind direction was from west, followed by northwest and southwest.
During the scheme, the wind direction was from the west initially, but later shifted to southwest and northwest,” said a scientist.
According to meteorological factors monitored by CPCB during the scheme, wind speed and mixing height was comparatively lower from April 17 to 25.