What’s wrong with odd/even Almost everything

If the Delhi government had bothered to read the detailed studies by NEERI and IIT Kanpur on the city's air pollution, they would have known that odd/even rationing of cars would do precious little.

Delhi’s odd/even scheme, under which cars with odd numbers are allowed to ply only on odd dates, and those with even numbers only on even dates, has become yet another faith war between believers and sceptics. Believers want it implemented elsewhere as well, including Mumbai.

It really isn’t a matter of faith. It is a matter for science and rationality.

To begin analysing the issue in any meaningful way, we have to start by looking at what pollutes the air. There are different substances that contribute to air pollution. They include particulate matter of different sizes, sulphur dioxide, carbon monoxide, nitrous oxides and hydrocarbons. Of these, only one has been making news of late — something called PM 2.5, which refers to particulate matter of size less than 2.5 microns. It is a new buzzword in the lexicon of the fashionable.

A detailed study on Delhi’s air pollution was completed in 2010 by the National Environmental Engineering Research Institute. The study, of 658 pages, was titled “Air Quality Monitoring, Emission Inventory, and Source Apportionment Studies for Delhi”. It categorised sources of pollution. “Area sources” such as smoke from cooking fires, open burning of garbage and leaves, dust from construction activities and emissions from diesel generator sets turned out to be one major category. Industries, including power plants, and vehicles were the other sources.

NEERI found that 52.5 percent of particulate matter was road dust. Area and industrial sources accounted for most of the rest. Vehicles contributed only 6.6 per cent to the total particulate matter emission load in Delhi’s air. This 6.6 per cent was the total for all vehicles, but not all types of vehicles contribute equally to polluting the air.

A second comprehensive study by IIT Kanpur, which was submitted to the Delhi government in December 2015, reported that two-wheelers account for 33% of particulate matter emissions by vehicles. Trucks account for 46%. Four-wheelers contribute only 10% to the particulate matter emissions by vehicles.

In other words, four-wheelers are the smallest source of particulate matter among all types of vehicles, and vehicles themselves are arguably the smallest source of particulate matter among all categories.

The reason I say “arguably” is because the quantities vary from place to place within the city, from time to time within the day, and from season to season as well. It’s all quite fluid, like air itself.

In fact, measures of the now infamous PM 2.5 would vary from inside a building to the road outside. If you smoke, chances are the levels in your room are higher than outside. Cigarette smoke also releases PM 2.5. Smoking a full cigarette means inhaling around 12 milligrams of it. You’d have to breathe in Delhi’s air for around two days to inhale as much PM 2.5 as you’d get from a single cigarette.

This is bad news for those who don’t smoke. Those who do smoke would do well to stop smoking before they start hyperventilating about PM 2.5 in the air.

It's much worse for those who use mosquito repellents. Burning a standard mosquito coil can release as much PM 2.5 as 75-137 cigarettes, according to a report on indoor air pollution by the World Health Organisation. Open cooking fires inside houses that use biofuels such as dung and wood can push up PM 2.5 levels to 10,000 micrograms per cubic metre, according to the same report. Delhi's PM 2.5 levels in December/January was around 226 on average.

The odd/even scheme didn't tell us any of this. Instead it made it appear as though there’s something in the air outside that’s killing us that will magically disappear if only people take out their cars on alternate days instead of every day. They did this despite having the studies from NEERI and the more recent one from IIT Kanpur, which clearly stated what the sources of pollution are. What's more, they knew they had those reports.

If the Delhi government, led by IIT graduate Arvind Kejriwal, had bothered to look at those reports they would have known in advance that the odd/even scheme was going to do very little to improve Delhi’s air quality. That is exactly what happened.

IndiaSpend, which has its own measuring devices, reported that “Air-pollution levels in Delhi rose 15% during the 15-day period (January 1 to 15, 2016) of the state government’s odd-even measure over the previous 15 days (December 17 to 31, 2015), according to an analysis of PM (particulate matter) 2.5 data”. The Hindu, which aggregated data from different sources, came to a similar conclusion.

The only data so far that suggests the scheme was successful to a degree has been a report in the Indian Express, jauntily headlined “Yes, Delhi, it worked”. How do we know Well, the authors, from University of Chicago and Harvard University, compared PM 2.5 levels in Faridabad and Delhi. They found that Faridabad’s PM 2.5 levels between Jan 1-15 have been higher than Delhi’s. The levels vary through the day, and the biggest dip in Delhi’s PM 2.5 level was around noon, though by 4 pm it had climbed back close to usual levels.

The study authors claim that “although absolute levels have increased both within and outside Delhi in the NCR, the levels in Delhi have seen a smaller increase. We argue that this can be attributed to the programme, and apply a popular impact evaluation method called differences-in-differences to quantify the reduction.” Their figure: 10-13% reduction on overall PM 2.5 levels.

This is impossible to prove or disprove, although access to their full data set would help.

The weather plays a big part in air pollution numbers, and there are variations even within cities. Besides, the graphs for Faridabad and Delhi show relative movement in other months as well, with Faridabad below Delhi in July 2015 and catching up with it around October. It is possible that pollution in Faridabad has been increasing; the difference-in-difference would increase in that case too. I wonder why these clever people concluded so confidently that it was Delhi's PM 2.5 going down from what it might have been, rather than Faridabad's going up, that accounted for the difference

The effects of odd/even are small at best. The most troubling bit in all this is that a very questionable policy was forced on a population without taking the dissenting voices into account. That is dictatorial, and even if supported by a majority, would be unacceptable.

A citizen has as much right to choose his own transport as he has to choose his own food. If the government banning meat during a Jain festival is wrong because it prevents a certain section of citizens from exercising their choice during that period, the government partially banning cars is also wrong for exactly the same reason. It prevents a certain section of citizens from exercising their choice.

The argument that this may be necessary for the greater good doesn’t wash, because the greater good, as far as pollution is concerned, is unlikely to be served by this gimmick. Real measures are required for that, and those measures have been listed out by NEERI and IIT Kanpur.

It’s a no-brainer that preventing half the cars from plying will reduce traffic. That this has been welcomed with eurekas says a lot. Pollution and congestion are indeed real and serious problems, but they will need real and sustainable solutions as well, not dramatic gestures. In any case, those who wish to sell their cars and use public transport are free to do so. I did this five years ago.

For those who like extreme solutions, I have a suggestion. Preventing people from having more than one child would address the issue of overpopulation and overcrowding in general.

Perhaps what you'd really like is for India to become more like China