New Delhi: Air quality was extremely poor on Monday despite the odd-even rule. According to scientists, it's too early to establish any link between the numberplate scheme and air pollution. They said even as compliance to the strategy remained high, weather played spoilsport on Monday.
A western disturbance (WD) over Pakistan and Afghanistan, which has already brought snowfall in Jammu and Kashmir, is responsible for the change in weather. "There is also an increase in moisture that makes it conducive for deposition of pollutants on water droplets. Wind speed is also very low. There can be several factors at play," said an official from the Met department.
There is a high level of PM 2.5, according to Delhi Pollution Control Committee's (DPCC) real-time air quality monitoring. On Mandir Marg, the levels were between 415 and 250 micrograms per cubic metres. In AnandVihar, PM 2.5 levels peaked to more than 500g/m³ in the morning and came down to around 300 later in the day.
The website of System of Air Quality and Weather Forecasting and Research (SAFAR) showed the day's average was significantly higher than January 4, 2015. There was rain last year on this day that led to washing out of pollutants. The wind speed on Monday had reduced to 1.7 knots compared to 2.77 knots on Sunday, which led to pollutants being trapped very close to the surface. Experts said no conclusions can be drawn on the odd-even formula as yet.
"There are a host of issues, cars are only a part of the problem. We can't determine the success or failure of odd-even strategy based on such small sets of data. But what we do know is that the arrangement hasn't collapsed on Monday, congestion is much less. This may have led to a reduction in emissions from vehicles but emissions and air quality are not the same thing," said Prodipto Ghosh, distinguished fellow, The Energy and Resources Institute (TERI). TERI has been analysing DPCC's data since December 24.
A DPCC scientist told TOI that due to a reduction in congestion, idling time is much less than earlier. "It is obvious that emissions would have reduced since moving around has become so easy and there are no jams. We will release data after we get sufficient evidence."
Amit Bhatt, strategy head, integrated urban transport at Embarq, said global examples show some link between congestion and air quality. In 1989, Mexico City implemented "Hoy No Circula" to ban the circulation of 20% of all private vehicles between 5am and 10pm on weekdays based on numberplates. Studies later showed a decline in fuel consumption, increased public transport ridership and better road safety. Similarly in Bogota, which imposed peak-hour vehicular restrictions in 1998, travel times reduced by 40-50% during those hours.
The Delhi government said on Monday nine out of 20 mobile monitoring units found PM 2.5 levels were lower than last year's average levels of the six stationary monitoring stations of DPCC.
"Air quality is severe in almost all parts of north India. It started becoming severe since 1am last night and peaked at about 9am reflecting a clear impact of hostile weather conditions. This only validates the need for emergency measures like the one we are piloting now in the city. Time has come to implement it with some more stringent measures and remove the exemptions on two-wheelers," said Anumita Roy Chowdhury, head of CSE's clean air programme.
