Yes, Delhi, it worked

The odd-even pilot reduced hourly particulate air pollution concentrations by 10-13 per cent. But for the longer run, a congestion-pricing programme may be better

Updated: January 19, 2016 8:34 pm
odd even, odd even rule, delhi odd even, delhi odd even rule , delhi pollution, pollution in delhi, odd even delhi, odd even news, delhi odd even news, delhi news Delhi’s odd-even policy is over. (Illustration by: C R Sasikumar)

Written by Michael Greenstone, Santosh Harish, Anant Sudarshan and Rohini Pande

Delhi’s ambitious odd-even pilot experiment to reduce the number of cars on the road, and pollution in the air, has come to an end — at least for now. But the question remains: Was it successful?

Answering this question is challenging. Air pollution data is limited and it comes from many different sources. Pollution also varies with time and weather conditions for reasons that have nothing to do with the odd-even pilot. Thus, simply looking at trends in pollution monitors cannot tell us what we need to know. Reflecting these challenges, different assessments so far have been contradictory, ranging from “complete failure” to “massive success”. In a rigorous new study, however, we conclude that the odd-even pilot did have some impact — reducing hourly particulate air pollution concentrations by 10-13 per cent.

To judge the scheme’s true impact, we compared Delhi’s pollution with the rest of the NCR, which has similar weather but didn’t fall under the ambit of the scheme. We did this between January 1-15, when the scheme was in effect, and in November and December, when it was not in effect.

Watch Video Debating The Success Of Kejriwal’s Odd-Even Formula

The first step was to analyse the effect of the odd-even policy on traffic. Anecdotally, there is a general consensus that there were fewer vehicles on the road during the scheme. We attempted to back this up with some hard data. Analysing real-time vehicle speed data from Uber Delhi revealed that during the odd-even programme, average speeds went up by a statistically significant 5.4 per cent (2.8 standard deviation from normal). This is an especially significant change given that radio taxi drivers are meant to stay within speed limits. If shorter trip times reflect fewer cars on Delhi’s roads, and if vehicle emissions significantly impact Delhi’s air pollution, then we may expect the odd-even pilot to translate into lower pollution. We should keep in mind that lower congestion itself reduces pollution as all vehicles (not just cars) spend less time on the road idling and in slow-moving traffic.

Having said this, the key question is to statistically quantify the level of impact. To do this, we first put together a dataset of hourly air pollution numbers from 23 monitors in Delhi, and three monitors from Faridabad, Gurgaon and Noida, where the odd-even policy was not implemented. This included both government and India Spend monitoring stations. Our results remain similar using only government data.
In December 2015, before the odd-even programme began, daily pollution trends in Delhi and the neighbouring regions were very similar.

delhi

This is not surprising considering that they have similar temperatures and weather patterns, and are affected in an equivalent way by crop burning and holiday periods. Starting January 1, while absolute pollution levels increased both inside and outside Delhi (for atmospheric reasons, as noted by other commentators), the increase in fine particle levels in Delhi was significantly less than in the surrounding region. Overall, there was a 10-13 per cent relative decline in Delhi.

It is possible to go one step further in our analysis by tracking pollution changes hour by hour, since the odd-even policy was only in effect from 8 am to 8 pm. The results are striking (see figure). Around 8 am, the gap between Delhi’s pollution and that in neighbouring regions begins to form and steadily increases until mid afternoon. As temperatures begin to fall, and pollution is less likely to disperse, this gap starts to close. We see another small gap emerge between 9-11 pm, which probably reflects the new limits on truck traffic in Delhi, which also came into force on January 1. Soon after midnight, the gap closes, and Delhi and neighbouring areas show similar pollution patterns until 8 am comes around again. When focusing just on the hours that the odd-even policy was in effect, our estimates suggest that particulates pollution declined by 18 per cent due to the pilot. For more details see http://j.mp/odd-even-QA.

While the odd-even policy reduced pollution during its first two weeks in effect, there are reasons to wonder about its ability to reduce pollution over the longer run. A natural concern is that the odd-even policy could easily be gamed or otherwise undermined. Further, Mexico City’s experience with the implementation of a similar policy suggests, it could even make pollution worse by encouraging households to purchase second cars that are old and very polluting.

A more durable effect on pollution might come from a congestion-pricing programme, in which drivers are charged for using the roads at certain places and times. This approach, which has been successful in places like London and Singapore, allows cities to effectively reduce car use at periods of peak congestion and pollution. The Delhi government should pilot the use of congestion charging, and invest any income from the charge in high-quality, high-capacity public transport with zero local emissions — which would again help to reduce demand for driving, congestion, and pollution.

Air pollution is shortening lives in Delhi and too many other places in India and elsewhere. The odd-even scheme has delivered over these two weeks, but may not over the long term. Furthermore, vehicles are only one source of pollution.

There is no shortage of creative ideas and potential pilots, but what is all too often lacking is evidence on which ones work as intended. In one effort to improve matters, the University of Chicago has launched a competition with the Delhi Dialogue Commission to crowdsource ideas for reducing air and water pollution (the Delhi Urban Labs Innovation Challenge). More generally speaking, governments need to accept that we don’t have all the answers to policy problems and adopt a culture of trying out new ideas, testing them carefully, and then deciding which ones to adopt at scale.

Greenstone, Harish and Sudarshan are at the Energy Policy Institute  at the University of Chicago, and  Pande is at the Evidence for Policy Design group at Harvard University

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  1. A
    Amiy
    Feb 10, 2016 at 4:42 pm
    Doubt about knowedge and intentions of the writers.
    Reply
    1. K
      K SHESHU
      Jan 19, 2016 at 11:36 am
      Public transport must be strenghtened for commuters. Otherwise, the vehicle holders would get another vehicle to compensate for odd/even rides without facing hurdles. Further other pollutants should be reduced in the long -run to produce good results.
      Reply
      1. A
        Ak21
        Jan 20, 2016 at 9:22 am
        The govt could have done it better. The odd-even only publicize Delhi govt.,s attempt to reduce problem , although no one talked about the main culprit , the industries. Its like policy wastage. The govt. is in the impression of doing something with investing power, money and time but not actually doing something that is efficient. We do not want to work hard but smart. But , nevertheless the effort and incentive should be praised of bothe , the people and the govt.
        Reply
        1. P
          priya
          May 22, 2016 at 5:08 am
          it was very good time in delhi.
          Reply
          1. A
            Amrita
            Mar 7, 2016 at 10:40 am
            Of course it worked Check out our graph during that time, we are a carpooling app and the number of users grew 2.5 times. Follow us on twitter, LinkdIn and facebook. Thanks, POOLMYRIDE
            Reply
            1. A
              Apurv
              Jan 19, 2016 at 7:09 pm
              Aamla tu khaa le mate, urr!
              Reply
              1. A
                Arnab Sur
                Jan 19, 2016 at 6:45 pm
                The government should follow what is suggested by IIT Kanpur. Gusswork and experiment with public will not work. Due to odd even people's traveling time increased by 1-2 hrs, causing huge inconvenience to all delhites. Govt should have discussed with India's best technical insute before implenting such immature plan. After all Kejri is an IITan, he should have given proper respect to his amlamater.
                Reply
                1. A
                  Amit Arora
                  Feb 10, 2016 at 4:02 pm
                  Take Free Ride of Rs. Rs. 250 during Odd Even Rules in Delhi by installing and using UBER Cab App on your Smartphone and Using Promo code "evbrcue" No conditions apply.
                  Reply
                  1. d
                    dv1936
                    Jan 18, 2016 at 7:26 pm
                    The basic issue is that something needs to be done, it is not s problem of Delhi alone, it is a national problem and there are many issues involved. The central government should coordinate a national policy. It should provide resources needed by the states to implement the policies on a war footing.
                    Reply
                    1. R
                      Raj
                      Jan 19, 2016 at 1:45 pm
                      Delhi air quality monitors SAFAR themselves show that the drop due to "odd-even" circus was NEGLIGIBLE and the decline caused by inconveniencing the ENTIRE city was not even enough to make Delhi air close to "safe" for humans. Even with Odd-Even, US emby was showing "Hazardous" levels of PM2.5 particles . So now what ? Will Kraziwala ban ALL cars ??
                      Reply
                      1. R
                        Raj
                        Jan 19, 2016 at 1:48 pm
                        Odd-Even is a USELESS attempt at Jugaad to solve a problem that didn't even originate in Delhi but originates in Punjab, Haryana and UP where lakhs of farmers burn their fields at once in winter. Instead of stopping that - we have useless solutions like odd-even. Further, compared to the number of cars in Shanghai or even most major European or American cities with Delhi - Delhi is far behind but still Delhi air is many times worse than European or american cities because industrial and agricultural pollution is the cause - not vehicular pollution. First shut down the power plants and factories in Noida and Meerut and Haryana - then talk about odd-even.
                        Reply
                        1. R
                          Raj
                          Jan 19, 2016 at 1:50 pm
                          Public transport is just like a cattle car with thousands of people packed into a metal box and dragged along like lambs to the slaughter. Its ridiculous and inefficient and there is nothing that will make it a replacement to cars of motorcycles.
                          Reply
                          1. S
                            Shashank Mittal
                            Mar 12, 2016 at 9:51 am
                            wow but this time i use easycarpooling for pollution free delhi
                            Reply
                            1. M
                              mithun
                              Feb 6, 2016 at 11:37 am
                              Everyone is afraid of the accident on a scooter while driving. This is why he would like to travel in the car. Traffic are not fast as you complaint. So there is no question of accident. Everyone should enjoy summer sun winter rains. get it only on scooter.
                              Reply
                              1. M
                                mithun
                                Feb 6, 2016 at 11:19 am
                                odd even was 30% worked new idea (1 car two person) when on road. if single person use 1 car please ban this type car uses. mostly public have 2 car. may be even odd number. than our traffic is little same. now try (1 car 2 two person). ex:- 10 person single ride in car. than 10 lac car on road if minimum two person use 1 car than 5 lac car save on road. but odd even was not reduce this type
                                Reply
                                1. N
                                  Niladrinath Mohanty
                                  Jan 19, 2016 at 11:19 pm
                                  Odd even formula is being made out as if it was an invention or an original idea of Arvind Kejriwal(AK). It had been tried in Paris and Mexico City earlier. AK deserves credit for having it tried it in Delhi. Furthermore,the formula by itself has not done anything. It was a mean to reduce the density of vehicles on the roads and almost half the number of vehicles were taken off.
                                  Reply
                                  1. N
                                    Neeraj
                                    Jan 19, 2016 at 4:58 pm
                                    It is critically terrible that the levels were still Hazardous but does it not matter that it was less than before. Lets not do anything till we have the big bang of all other plans ready to implement, yeah that sounds great .. or does it ?
                                    Reply
                                    1. N
                                      Neeraj
                                      Jan 19, 2016 at 4:56 pm
                                      While the sources u name are valid and have been talked about by the delhi gov. Plans to shut a power plant and to acquire vacuum dust remover .. in addition to 4 other ideas are being worked at. But, I don't get why not talk about odd-even before that. Why can't the above data be discussed?
                                      Reply
                                      1. N
                                        Nityananda
                                        Jan 19, 2016 at 3:35 am
                                        A technical insute in LIma, Peru ( UTEC) has tried out a unique billboard design that scrubs the air around a dusty site and then releases the purified air back . This system uses very little power to run and emulates the cleanup job that can be done by around 1200 trees. UTEC has tied up with an advertising firm for spreading this technology. This looks to be very useful for construction sites in Delhi and other cities. It is surprising that the authors have not mentioned this innovation as one of the possible ways to combat pollution in Delhi.
                                        Reply
                                        1. H
                                          hardik
                                          Jan 20, 2016 at 7:14 am
                                          Why dont you think about electric cars... Problemo solved... lol, u may do not have permission from the oil lobby right! :P
                                          Reply
                                          1. H
                                            hardik
                                            Jan 20, 2016 at 7:16 am
                                            Why is no body talking about electric cars? oil lobby?
                                            Reply
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