NEW DELHI: The exemptions announced for Delhi government’s odd-even vehicle policy have diluted the measure and it may not meet the goal of reducing air pollution by a significant amount, experts said.

With restrictions being lifted for two-wheelers and single women driven cars, a big chunk of vehicles will continue to run on the road. Two-wheelers, in particular, are responsible for about 33% of particulate matter (PM) emissions in the transport sector, second only to trucks, according to the recent draft IIT Kanpur report.

Any pollution control measure would need to target two-wheelers since these account for 51 lakh out of the 89 lakh registered vehicles in Delhi, felt experts.

They were hoping that the fortnight-long trial would push both car and two-wheeler users towards public transport and give Delhi government clues on how to optimize public transport and para-transit resources. Recent assessments by Centre for Science and Environment had revealed that fleet utilisation of Delhi Transport Corporation was far lower than that of Bangalore and Chandigarh.

Even the number of kilometers buses do in Delhi are lower than Bangalore or Chennai, with a large number of trips here being cancelled because of congestion.

“The moment road space is freed up during the odd-even days, the fleet utilization would pick up. We were hoping that through the trial, Delhi would figure out how to optimize public transport, especially buses. But now it’s all diluted,” said Anumita Roychowdhury, head of CSE’s clean air programme. If the exemptions are not cancelled, the odd-even formula is being tried on only 20% of Delhi’s vehicles.

CSE which was consulted by the government earlier on measures to counter pollution in the city, said in a statement on Thursday, “If this segment is left out and a sizeable number of cars are also allowed because of the exemption granted to single women drivers, the overall effectiveness of the programme will be compromised. It cannot act as an emergency measure to bring down peak pollution levels. CSE would urge the government to bring two-wheelers within the mandate of this programme.”

The paradox with motorcycles or scooters and bikes is that they are most space and fuel efficient but due to their combustion technology, one two-wheeler is estimated to emit almost as much as a BS-III standard car.

According to an analysis by International Council on Clean Transportation (ICCT), two-wheeler emissions include particulate matter (PM), carbon monoxide (CO), nitrogen oxides (NOx), hydrocarbons (HC), sulphur oxides (SOx), which vary with the fuel’s sulphur content.

Even though the amount of PM emissions are less toxic and lower compared to diesel emissions, the sheer number of two-wheelers makes them an important personal vehicle segment that needs to be addressed. The chemical nature of PM emissions from bikes is very different from that of diesel, which is why bikes are considered a lesser evil, CSE researchers said. IIT Kanpur’s draft study also revealed that 60% to 90% of PM 2.5 emissions in certain parts of the city are from diesel vehicles.

Amit Bhatt, strategy head of integrated urban transport at Embarq said it would be a better idea to follow the odd-even system that’s tried and tested in Latin America. “In Bogota, only a certain number of VIP, armoured or security vehicles, adapted handicapped vehicles and emergency vehicles are exempted. They have never exempted two-wheelers or women,” Bhatt said.