The number of vehicles were more on Delhi's roads during the second phase of Odd-Even, TERI said.
Regularising the Odd-Even scheme for vehicles in Delhi will not help in reducing pollution level in the national capital, and should only be used as an emergency measure, The Energy and Resources Institute or TERI said today.
The Odd-Even rule, for example, should be used during the winter season when the air is heavier and closer to the surface which leads to more pollution, referred to as winter pollution, the key reason behind increase in asthma cases in the capital, TERI said.
"The results of the two phases of Odd-Even scheme in Delhi suggest that it is useful only when high pollution episodes are expected. We do not see merit in regularising the scheme," Dr Ajay Mathur, Director General, TERI, told NDTV.
Dr Mathur said the number of vehicles on the roads were more during the second phase of Odd-Even, which was implemented from April 15-30, as compared to the first phase which took place in January.
"In Odd-Even 1 the number of cars on the roads were 21 per cent less than the week before and in Odd-Even 2 the number of cars on the roads were 17 per cent less than the week before, which means more cars during Odd-Even 2," he said.
Particulate Matter 2.5 or PM 2.5 is the dominant pollutant in the capital. As private cars have limited contribution in the PM 2.5 levels in the city, the scheme led to only marginal reduction in the pollution level. In winters, the Odd-Even experiment led to nearly seven per cent reduction in 24-hourly PM2.5 concentrations; however, in summers, when the pollution levels are relatively lower and the share of vehicular sources is lower too, the impact of the scheme is further reduced.
Launching an impact assessment study on the Odd-Even plan today, TERI said there is a need to step up controls beyond the traffic regulation scheme, like a better transportation system to encourage car users to shift to public transport.
TERI has also recommended various other options that Delhi should adopt in order to reduce pollution. Congestion pricing can be an alternative to the Odd-Even scheme, it said. Congestion pricing is based on 'pay-as-you-use' principle in which a vehicle is charged on entry into restricted zones and times.