Regularisation of 'odd-even' will reduce its impact: TERI

Regularisation of the 'odd-even' scheme will "reduce" its impact and it should only be used as an emergency measure, a green body on Tuesday said, underlining the need for implementing alternative measures like "congestion pricing" to lessen the number of vehicles on roads to tackle air pollution.

The Energy and Resources Institute (TERI) which released an impact assessment study on the two-phases of odd-even scheme observed that as private cars have limited contribution in the PM2.5 levels, the scheme yielded only "marginal" reductions (4-7 per cent) during both the phases. 

TERI observed that the impact of the scheme with respect to traffic counts, average speeds and air quality declined during the second phase in comparison to the first phase and the decline could be probably due to people opting for "second cars with alternative number plates, installations of CNG kits or enhanced use of taxis".

"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. "A more sustainable approach for dealing with air pollution not only in Delhi but also in other metropolises would be congestion pricing, which is a far more effective option," Director General of TERI Ajay Mathur said. Congestion pricing is based on a 'pay-as-you-use' principle with an aim to reduce the number of vehicles and in turn encourage modal shift by charging vehicles on entry in restricted zones and times. This can be complemented by providing exemptions to higher-occupancy vehicles. 

TERI said that such a model has proved to be successful in cities such as Singapore, London, Sweden, Rome, Durham, Seoul, San Diego etc. The congestion pricing scheme can be first tried out in different ways including, all across congestion pricing, identification of low-emission zones and road-wise congestion pricing, TERI said. TERI also urged the government to ensure the earliest possible introduction of BS-VI vehicle and fuel quality norms, real-time monitoring and reporting of industrial emissions in NCR and the need for business models to convert agricultural wastes into energy using biomass gasification technologies.

Sumit Sharma, fellow at TERI, said that the measures, which were taken, were more to control particulate matter rather than Oxides of Nitrogen (NOx). "We need multi-sectoral measures for the whole NCR to effectively reduce air pollutant levels, which calls for regular air quality management plans based on scientific studies," he said.

While TERI acknowledged that the scheme was successful in raising public awareness on air pollution as well as in improving traffic speeds, it also cautioned against the regularization of this scheme, saying the rule should at best be used as an emergency measure. The body said that during phase II of the scheme, the general variation of PM 2.5 concentration due to daily changes in local emissions, meteorology and background concentrations (influences from outside Delhi) was 42 per cent.

The reduction achieved from the scheme during this phase seems too small (4 per cent) to be captured among the other more dominating factors. 

TERI said that as in the case of other cities in the world that have tried out the scheme, people could look for alternatives by purchasing new or old cars which would, over a period of time, neutralise and negate the positive impacts. "This is likely to happen as the public transportation system is not reliable and attractive enough to encourage the car users to shift to public transport.

"Hence, the odd-even scheme should be used only as an emergency measure when the pollution levels are expected to be very high like winters. Regularizing it or its frequent use may only reduce its impacts, unless public transportation is improved and sales of alternative vehicles are checked," it said.

TERI emphasized that air quality management plans should be based on scientific studies that are updated every 3-5 years and air-quality targets must be defined for each year and strategies must be enforced to achieve them in line with these plans.

TERI said that during phase-II of the scheme, the averaged PM2.5 concentrations at five locations were 1.4-4.3 times higher than prescribed 24-hourly standard, NO2 concentrations were 0.6 1.36 times the prescribed standard while PM10 levels were 1.8 4.0 times above the prescribed standard.