Against this backdrop, the Delhi government has just concluded the initiative to mitigate the capital’s air pollution by reorganising private four-wheeler vehicular traffic, from January 1-15, in a manner that these would run on odd-even dates according to the last digit of their number plate being other odd or even. Various central and state organisations—Central Pollution Control Board (CPCB), System of Air Quality and Weather Forecasting and Research (SAFAR), Delhi Pollution Control Board (DPCB)—and some private institutions like the Centre for Science and Environment (CSE) and The Energy and Resources Institute (TERI) have been collecting data on various parameters of AQI, specifically to understand the efficacy of this exercise.

The odd-even scheme in not something new and has been tried in various other countries by adopting somewhat different methods. For example, starting 1992, Amsterdam (the Netherlands) reduced vehicular traffic and parking spaces by half in city centres by 2002, promoting the use of bicycles for commuting. In 1990, Bogota (Colombia) started the idea of reducing the number of cars through investing in an efficient Bus Rapid Transport Scheme (BRTS)—which unfortunately failed in Delhi due to bad planning, though it has proved to be very successful in Ahmedabad—and by imposing vehicle number plate limits during morning/evening peak hours in 1998. Likewise, Stockholm (Sweden) imposed a congestion tax, thereby reducing congestion by as much as 30-50%. Seoul (South Korea) launched a no-driving day programme in 2003, for which citizens got incentives such as reduction in auto tax. Several other cities such as Beijing, Paris, Mexico City, Singapore and Santiago have also experimented with similar schemes to reduce congestion and hence pollution.

Now, while we can applaud the Delhi government for this rather politically-bold initiative and for creating awareness among the masses for the dire need of reducing air pollution, the moot question is whether Delhi’s odd-even scheme has resulted in reducing air pollution? If yes, to what extent? The jury is out and debates are raging on. However, evaluating its success, in a truly scientific manner, has posed some problems because of three reasons.

First, pollution levels depend on location, time of the day, and even the height at which the data is collected; for instance, mobile vans collect data at a lower height than fixed air stations, and various agencies’ data differ in these respects. So, the question is, which data to use?

Second, weather conditions—such as temperature, humidity and wind speed—during the 15 days of the scheme were not the same as during the reference period that was chosen for comparison. To arrive at a correct conclusion, these conditions should match.

Third, we need to devise a new index—which takes into consideration the effect of weather conditions and location aspects—before any realistic evaluation can be done. The devising of such an index would require ingenuity and objectivity on the part of statisticians/researchers; for this, we may utilise the services of either the Indian Statistical Institute (ISI) or the Central Statistical Organisation (CSO).

There is another point here. Even after devising a good new AQI, the real question—whether the odd-even scheme can, in itself, reduce air pollution—remains unanswered. It is because the contribution from the entire fleet of vehicular traffic, and not just cars, to the total air pollution is 9% for PM10, 20% for PM2.5 and 36% for nitrogen oxide. The major contribution of PM10 of 66% and PM2.5 of 36% is from road dust and construction activities. The industrial stack also emits significant 10% each of PM10 and PM2.5, and 52% of nitrogen oxide. Then why target only the passenger traffic sector to reduce air pollution?

This scheme cannot be a sustainable solution in the long term. Even in other countries similar schemes have been introduced on a temporary basis. The number of cars and two-wheelers on the roads would reduce automatically if the public transport system—DTC bus network and Metro Rail—is made more efficient, frequent and elegant, so that even the well-heeled/elite class would travel, as in other countries. From January 1-15, this class of Delhiites increased the use of radio taxis, which is counter-productive for the cause.

Manhattan is a case in point. Despite being one of the richest districts in the world, 75% people are without cars. A lot of people travel by New York City public transport, which allows them to go car-free. Such examples from rich nations can be multiplied. Therefore, a more holistic approach consisting of a bouquet of other measures has to be adopted for Delhi.

* Ensuring dust control at construction sites and in transporting construction material, and using vacuum cleaners for road cleaning.

* Introducing feeder services to provide first- and last-mile connectivity with metro stations.

* Enforcing retrofitting of diesel vehicles with particulate filters.

* Stopping open biomass burning. Also, biomass-based power generation units should be made to adopt proper scientific technology to avoid harmful emissions.

* App-based cabs and aggregators should work, in their own economic and larger social interest, to promote carpooling. Companies like Ola, Uber and Meru have already started working in this direction, besides some corporate entities. Tripda, the Brazilian carpool start-up, believes that India can be one of the top markets of the world for carpool.

* Decongesting pathways of encroachers, maintaining pothole-free roads, and avoiding confusing traffic systems like the abandoned BRTS tracks.

* Introducing staggered working hours by getting major employers on board to avoid traffic congestion on key crossings during peak hours.

* Providing dedicated bicycling tracks to the citizens for promoting the use of bicycles.

* Promoting conversion of cars to CNG (60,000 cars already converted during the odd-even scheme period) by opening new CNG stations and increasing capacity of existing ones.

* Expediting the expansion of metro network, including the ring road tracks, since the efficacy of the Circular Rail, which runs only three times in the morning and evening, is in doubt.

* Ensuring the introduction of BS-VI emission standards by the stipulated time, i.e. April 2020.

The odd-even formula does bring out the urgent need to combat Delhi’s air pollution, but it is not a sustainable solution. Besides evolving an improved AQI, the government must take immediate measures as suggested to effectively combat air pollution. Some of these measures, in fact, are low-hanging fruits wherein one only needs administrative will to implement current laws. Such steps can discourage the use of personal cars and two-wheelers, obviating the need for an odd-even regime.