The odd-even vehicle restriction scheme could be helping clean up Delhi’s air, the city’s pollution control authority has said, although its findings are at variance with those of other air monitoring agencies.
The Delhi Pollution Control Committee (DPCC) said PM 2.5 levels were within the permissible limit of 60 micrograms per cubic metre of air (µg/m3) at 42 of 74 locations in the city on April 16. This, it said, was an improvement over the days preceding the scheme – which requires odd and even-numbered vehicles to ply on alternate days of the week.
|PM 2.5 denotes particulate matter with a diameter of 2.5 microns, which can penetrate deep into the lungs and cause the most damage.|
According to DPCC mobile vans stationed at various spots across Delhi that day, nearly 69 locations across the city registered PM 2.5 levels below 100 µg/m3 while 45 locations showed PM 10 levels below 200 µg/m3. A concrete assessment will be made after studying the impact for a few more days, officials said.
These findings, however, were at odds with TERI’s claims that many places across the city witnessed an over-threefold increase in PM 2.5 levels on April 16 as compared to April 12 (before the scheme was implemented). Data from the research institute stated that while PM 2.5 levels at Anand Vihar stood at 168 µg/m3 on that day (as compared to 55 on April 12), it was 151 µg/m3 at Punjabi Bagh (an almost four-fold jump from 41 on the earlier date).
The Delhi government was forced to take the road rationing measure for the first time in January as pollution levels touched alarming levels. While most residents agreed that the scheme helped bring down vehicular congestion in the first phase, its success in reducing pollution levels is still being debated. Vehicular emissions are a big contributor to air pollution, but other factors such as construction work and dust also play a major role in its increase. Moreover, two-wheelers have been left out of the scheme even though they emit more pollutants than cars.
The Ministry of Earth Sciences’ System of Air Quality and Weather Forecasting and Research (SAFAR) , on the other hand, supported the DPCC’s claims – stating that air pollution levels had undergone a steady decrease between Friday and Sunday. This was evident from the slump in PM 2.5, PM 10 and ozone levels recorded across the city over this period, it said.
Ozone levels in the atmosphere on Sunday, however, were the lowest since the beginning of the month.
According to SAFAR, the average PM 2.5 concentration in Delhi on Tuesday is expected to be 80 µg/m3, 20 points more than the standard level. The average PM 2.5 concentration was 78 µg/m3 on Monday.