Odd-even scheme: Less congestion reducing local pollution, experts say

Less congestion in Delhi owing to the odd-even car rationing scheme is shielding people from "direct exposure" to pollutants, especially in and around areas of high car density such as traffic junctions, experts opine.

The experts unanimously endorse that a reduction in the volume of cars was simultaneously bringing down levels of gaseous pollutants like oxides of nitrogen, sulphur dioxide and black carbon, which is a mixture of road dust and vehicle fumes.

However, they also warn against expecting any dramatic reduction in the amount of respirable particulate matters, PM 2.5 and PM 10, which depend on a host of atmospheric parameters.

The measures aimed at curbing pollution came into force on January 1.

Dismissing murmurs that the pilot plan has yielded little gains until now, ecologists and urban planners contend while hostile weather conditions may be limiting the gains, it would definitely restrict the peak levels from spiraling out of hand.

Raj Cherubal of Chennai City Project said lesser congestion has proven that "there is space" on Delhi's roads for buses and measures like BRTS, while Shreya Gadipalli of Institute for Transportation and Development Policy said the policy has created a platform "for a dialogue".

Anumita Roychowdhury of Centre for Science and Environment said that a sharp drop of pollutants from the peak levels has been observed over the last few days and added, "When vehicles slow down due to congestion they emit more. Free flow of traffic helps prevent that."

"Congestion also causes pollution and it affects the lower middle class more who are directly exposed to criteria pollutants like oxides of nitrogen, sulphur dioxide and black carbon. Pollution should not be looked at only from the point of view of the amount of suspended particulate matters like PM 2.5 and PM 10. Cars not only take most of the space but also affects common people the most," Madhav Pai of EMBARQ said.

Holding it a "much needed start", Samar Halarnkar of IndiaSpend, a portal that runs a network of 'low cost sensors' across Delhi, said that enforcing the car rationing scheme is not enough and the government needs to focus on implementing all the other measures like shutting down the coal-based Badarpur thermal power plant.

Over 1.5 lakh cars were added to the city's roads this financial year along with 3.5 lakh bikes and scooters, taking the number of total registered vehicles whopping 88.27 lakh, as per Delhi Statistical Hand Book 2015 released by the city government.

Cherubal argues that odd-even should be seen in the context of tactics towards "better quality of life" and that the Aam Aadmi Party government should immediately announce a comprehensive action plan with timelines on multi-modal integration, new buses, BRTS, common ticketing system, quota on buying cars among others.

"Congestion at junctions, where drivers idle engines, means higher local pollution. Lesser congestion due to odd-even proves there is space on Delhi's roads for buses and measures like BRTS which is not obvious on congested roads. So odd-even and such can be tactical," he said.

Cherubal, who pioneered the 'car-free' day scheme in Chennai, also sought to point out that big cars or SUVs take up disproportionate amoung of space on the limited road, carrying disproporationately smaller percentage of commuters.

"So even if cars/SUVs use cleaner fuels and emit less smoke, what about all the other forms of pollution it causes inlcuding congestion, noise pollution thereby eroding quality of life?" he asked.

Roychowdhury, who heads CSE's clean air campaign, said on the first day of the enforcement of the scheme, a sharp drop in the level of pollutants was observed despite wind speed being lesser compared to the previous day.

Gadepalli of ITDP, that has implemented Ahmedabad's BRTS system, said expecting the odd-even policy to dramatically reduce pollution levels overnight would be "silly" as there may be existing residues in the air.

"The primary goal was to get people thinking about pollution due to unmitigated use of cars and explore alternative mobility solutions, especially public transportation. This has created a platform for a dialogue for what kind of a city we want -- one where our children die of suffocation and unsafe streets, or one where they can live a happy and full life," she said.