Delhi's odd-even scheme has no impact: study

The 15-day odd-even formula in Delhi in January 2016 failed to improve the national capital's air pollution levels as there was barely any impact on the vehicular pollution load, a new study has found, confirming what was suspected all along.

Under pressure from the courts to clean up the Delhi air, the Aam Aadmi Party government introduced the road-rationing scheme on a trial basis to see if such a measure can really help.

Though it unclogged the traffic in the peak hours, the odd-even rule didn't result in the anticipated traffic emission reductions in January 2016, Indian scientists reported in the latest issue of the journal Current Science.

The researchers identified two reasons for the scheme's failure  - people shifting their travel schedule to beat the 8 am-8 pm restrictions and a sharp rise in the number of buses, auto-rickshaws, taxis and two-wheelers that were exempted from the road rationing rule.

The world's second most populous mega-city, Delhi has India's highest number of personal vehicles, with a registered fleet of 29 lakh cars and jeeps and 61 lakh two-wheelers.

Every year, on an average about 1,50,000 cars and 3,00,000 two-wheelers are being registered in Delhi.

The AAP government brought in the odd-even formula in the lines of similar schemes that were tried in Beijing, Mexico City and Sao Paulo.

To check whether the road rationing scheme made any difference to Delhi's air, a team of scientists collected air samples from various sites on a strategic arterial road that connects south-west Delhi to central Delhi.

The samples were analysed at the atmospheric chemistry laboratory of the Indian Institute of Science, Education and Research (IISER), Mohali.

The scientists examined the levels of carbon monoxide, carbon dioxide, methane and volatile organic compounds (VOC), which they claimed were better suited to monitor the vehicular pollution rather than pollutants like sulphur dioxide, ozone and particulate matter (PM-2.5 and Pm-10), which can come from sundry other sources.

The VOC numbers between 7-8 am is 1.6 times higher than the average value, suggesting a lot of early morning movement to bypass the odd-even scheme, said the team comprising researchers from India Meteorological Department, Indian Institute of Tropical Meteorology, Pune and IISER Mohali.

Moreover, the emissions from the increased fleet of exempt vehicles, the study says, have offset the reduction of emissions accomplished by controlling personal four-wheeler vehicles.

This is the second scientific study on the failure of the odd-even formula. Another team, led by scientists at IIT-Kanpur, last year showed how road rationing failed to reduce the level of particulate matter in Delhi.