“When the facts change, I change my mind. What do you do, sir?”, John Maynard Keynes is, perhaps apocryphally, reported to have asked. This is a question I would like to hear Arvind Kejriwal answer, now that he has announced a third spell of the odd-even scheme for 10 days in November.
Citing studies by Chicago and Harvard universities, Kejriwal claimed that earlier spells of odd-even saw a 10 per cent to 13 per cent reduction in pollution. This was his ground for imposing the scheme again this November.
But these American studies are not definitive. Several others, done by Indians, come to different conclusions. At least one says pollution increased during the odd-even period. Another points to a similar finding.
I suppose the kindest is a study by IIT Delhi, co-authored by professor Dinesh Mohan. It found that air pollution reduced by 2 per cent to 3 per cent when the scheme was first introduced in January 2016.
However, two others are not so generous. One done by researchers from several institutions, including the ministry of earth sciences, published in Current Science in March 2018, “conclude(s) that the odd-even rule policy measure did not result in reduction in primary traffic emissions. Instead, it appears that there was an overall increase in traffic emissions”. Another, by the Central Pollution Control Board, uses evidence from Dilshad Garden to arrive at a similar verdict. Carbon monoxide and PM2.5 did not decline but rose appreciably.
Barun Aggarwal, co-founder, Care for Air, says 13 different variables contribute to Delhi’s air pollution. They include power plants, construction dust, the burning of solid waste and field stubble, diesel generators and brick kilns, which may have moved just outside the city but still affect it. IIT Kanpur says the contribution of vehicular emissions – comprising trucks, buses, cars, auto-rickshaws and two-wheelers – is between 20 per cent and 25 per cent. The contribution of cars is only 10 per cent. If half of them are disallowed on any day, that should ideally reduce to 5 per cent.
However, there are at least two reasons for believing that may not happen. During odd-even, the use of taxis and auto-rickshaws, which rely on old technology and poor quality fuel, increases substantially. Second, studies have found the use of cars also rises sharply, particularly during the hour before the daily ban starts. Consequently, as the Current Science study says, “The emissions from the increased fleet of exempt vehicles therefore appear to offset the reduction of emissions accomplished by controlling personal four-wheeler vehicles/cars.”
So, what’s the conclusion? According to studies, the odd-even policy doesn’t work – actually makes the problem worse – or the improvement is so marginal it’s not worth the cost and inconvenience. And if you think about it, this is a pretty common sense conclusion. Aggarwal says three main criteria determine automobile-caused air pollution – the number of cars on the roads, the number of kilometres driven by each car each day, and the emission per kilometre per car. Odd and even reduces the number of cars but seems to increase the number of kilometres driven each day by each car and, therefore, the emission per kilometre from that car.
All of this is made worse by the exemptions. On previous occasions, they have included CNG vehicles, women drivers, taxis, three-wheelers, two-wheelers, ambulances and the cars of ministers and judges. Taxis, three-wheelers and two-wheelers are among the worst polluters. Of the latter, there are over 7.3 million on the roads each day.
So, now, what might be Kejriwal’s answer to my opening question? It was understandable in 2016 to experiment with odd-even because we then thought it could make a difference. Now that we know it doesn’t – or, indeed, makes matters worse – haven’t the facts changed?