While the Delhi government’s spirit of experimentation is to be lauded, the right lessons need to be learnt from the odd-even trial.
It is now amply clear that no credible data supports the
Delhi government’s claim that the
odd-even trial has reduced pollution or improved air quality. In fact, the quality of air in the first week of January was worse compared to previous weeks. Data obtained from the
National Air Quality Index (NAQI) portal shows that air has been toxic all through this winter. While averaging the AQI values across eight pollution-monitoring stations in Delhi, for which adequate data was available, we found that November had seven days in the ‘severe’ category, 19 in the ‘very poor’ category, and four in the ‘poor’ category; December saw 20 days fall under the ‘very poor’ category and 11 days under the ‘poor’ category. In the first week of January, all seven days fell under the ‘very poor’ category. Even the peak value of PM2.5, which the government claims has been lowest during the odd-even trial compared to earlier peaks this winter, is either comparable or just slightly lower to peaks observed from the beginning of December,
The Hindu’s analysis shows. On average, AQI values for Delhi for the first week of January were 20 to 25 per cent worse than during the preceding week.
Findings from other studies
Similar trends can be observed from data from the Indian Institute of Tropical Meteorology’s System of Air Quality and Weather Forecasting And Research’s monitoring stations, which showed that the quality of air continuously deteriorated from December 25, with pollution levels being “severe” on four out of the first eight days of January, worse than the previous week. Data from either the Delhi Pollution Control Committee or the Central Pollution Control Board could also not show any improvement in air quality.
It should be clear that the scheme did not worsen air quality; meteorological conditions did, but the scheme was not able to mitigate this impact. For one, wind, which disperses pollutants, has fallen consistently in speed since December. On the other hand, though higher temperatures — the case this year compared to the same time last year — usually improve air quality, the concentration level of particulate matter in January 2016 is twice as much as it was during January 2015.
Simply put, it is disingenuous for the government to claim either that the odd-even trail has improved air quality or that, but for its scheme, the air quality would have been worse given the weather conditions, as Transport Minister Gopal Rai has claimed, since it has simply no way of establishing this without better modelling.
Vehicular pollution
More worryingly, it now seems quite clear that this is what we should have expected. What is clear from data about sources of air pollution in Delhi is that cars are not the major polluters. The draft report of the Indian Institute of Technology, Kanpur, which was commissioned by the Delhi government in 2013, on the sources of particulate matter finds that vehicles contribute to 20 per cent of PM2.5 concentration. Among them, trucks and two-wheelers together contribute to 80 per cent of pollution; cars, 10 per cent. This means that the contribution of four-wheelers to air pollution in Delhi is just 2 per cent. On a given day, when half the cars are taken off the road during the odd-even trail, with additional exemptions, only a 0.5-1 per cent reduction in pollution can be expected. This could be marginally higher depending on the impact of the wind.
Similar findings have been reported previously. In 2008, a study by the National Environmental Engineering Research Institute attributed only 6.6 per cent of particulate matter emissions to vehicles. At the more generous end, SAFAR at the beginning of the odd-even experiment estimated that a 15 per cent reduction in PM2.5 levels could be expected. Despite being in possession of these reports, the government repeatedly claims that cars are the main cause of Delhi’s pollution.
None of this is to say that the experiment should not have been conducted; on the contrary, in fact. India’s federalism allows for a vast array of public policy experiments, and the Delhi experiment is one of the few related to environmental pollution in India. The Aam Aadmi Party’s ability to take bold steps, convince people to take ownership of these steps, and force both a conversation and behavioural change is truly remarkable. But an experiment must be built around an open-ended question, which has not been the case so far. The government has not honestly answered the question, “Did this scheme improve air quality?” The answer is, at worst, a ‘no’, and at best, ‘we cannot say’. The government has instead made a virtue of decongestion, which was not the stated objective of the experiment and is an obvious outcome.
Implementing other measures
The government, in the spirit of experimentation in which it initially announced the scheme along with a series of other measures, must continue to try to see what improves Delhi’s air quality. Perhaps the odd-even scheme will show a positive impact in the coming weeks, though it should be declared a success only after weather conditions are incorporated into the analysis. An odd-even trial in the summer months might be more useful to isolate its impact. The government’s proposal to vacuum-clean roads in April is promising, given that the IIT Kanpur study attributed 38 per cent of pollution to road dust. During Beijing’s ‘red alerts’ issued in December 2015 and January 2016 over levels of particulate matter that Delhi regularly experiences, restrictions on car usage were only a part of a bouquet of emergency measures imposed. Other measures included temporary controls on industry and construction, and banning the use of fireworks. Delhi would do well to react similarly on multiple fronts.
There are other lessons to be learnt from the odd-even experiment. Perhaps the increase in use of public transport by the elite could put pressure on the government to improve it (though this lesson is to be learned more by the Delhi Transport Corporation’s bus system than the metro system, which is already used more than buses by the rich). Can the AAP’s remarkable community-organising abilities drive further behavioural change away from single-use cars? The greatest success of the scheme has undoubtedly been the fact that emergency levels of pollution are now being hotly discussed by citizens. The AAP government has before it a unique opportunity, which it should not squander away by asking the wrong questions or refusing to hear the answers to its questions.
rukmini.s@thehindu.co.in and samarthbansal42@gmail.com
