Delhi Air Pollution – How is the way we think about it so so wrong?

(A version of this article appeared in Firstpost:

The prestigious medical journal, The Lancet recently reported that air pollution is associated with 6.5 million deaths annually, and as the Lancet rather poetically puts it, is a “killer indifferent to political agendas and that cannot be contained by borders”.

Don’t we know it?

Because pollution is a silent and slow killer, we, like the proverbial frogs in a boiling pot, are indifferent to problem until too late.

Besides pollution is such an abstract monster – like trying to grasp at air.

So let’s break it down.

First, air pollution falls into two types – indoor and outdoor. These differ in both where they occur and why they occur. Let us focus on outdoor pollution for now.

Premature deaths from outdoor pollution total about 3 million annually, and, in a bit of worse news, are projected to rise to 4.5 million deaths by 2040.

Closer to home, India loses about a million people prematurely each year to outdoor pollution.

This is a lot.

There is a climate angle as well – some of the particles that cause the pollution also warm the climate. Black carbon, as the soot particles are called, is thought to be the second largest warming force after carbon dioxide – though there is considerable uncertainty over this.

Winter is coming…to Delhi

A traffic policeman wears a mask to protect himself from dust and air pollution as he signals to drivers in New Delhi

Figure 1: Traffic Cop in Delhi (Courtesy Reuters)

New Delhi, whose winters are infamous, not for the arrival of the White Walkers but for the smog, presents a great place to understand what to do, and equally importantly, what not to do.

How bad is the winter in Delhi?

Very Bad. My friends in Delhi all have air purifiers running indoors and some wear masks as they step outside – they are fortunate, as they can afford to do so. Many can’t.

I used to pride myself on the ability to snort dirt and not get any allergies. A visit to Delhi in the winter, broke this arrogance with an asthmatic attack.

This is anecdotal evidence. What about the hard facts?

Delhi routinely tops the most polluted city in the world rankings.

Between 3000 to 30,000 deaths in Delhi annually (Oh, the state of data!) are attributable to air pollution, with the damaged lung capacity of children adding a far more permanent cast to the problem.

Can we solve this problem?

Treating cancer with water

Let’s start with a medical analogy.

Suppose you had a fever. When you visited the doctor, the doctor would ask you a set of questions and perhaps order some blood tests to understand the cause of the fever. Paracetamol might ease the symptoms, but it is important to understand the cause of the fever. A bacterial infection needs antibiotics, cancer needs an entirely different treatment regime, while a viral flu needs plentiful hydration and rest. Treating cancer with hydration won’t work.

But puzzlingly our leaders seem to be doing precisely that. Hold that thought. We’ll come back to it.

The dynamics of pollution

Pollution is a catch-all term: among its constituents ranks Carbon Monoxide, Sulphur dioxide, Ammonia, and importantly particulate matter, or PM. They each come from different sources or causes – the exhaust fumes from our vehicles, the burning of solid waste in cities, the burning of agricultural waste in the faraway fields of other states, the dust from construction sites to name just a few.

Let us narrow our focus on PM, or particulate matter. These are tiny particles, many many times smaller than the thickness of a human hair, which wreak havoc in our lungs when we breathe in air that contains them. PM is further classified into two broad classes: PM 10 is about 5 times smaller than a human hair, while the much smaller PM 2.5, whose smaller size allows it to penetrate that much farther and stay there, damages our lungs and has been linked to both cancer and heart disease.

It is important to recognize that PM is also a catch-all term. Individual particles have a chemical signature that suggests their origin. For example, a presence of a compound called levoglucosan suggest biomass burning, while the presence of another compound called hopane suggests the pollution had a vehicular cause.

Perhaps the most important pattern to recognize about PM-levels is that the causes vary by season. Given that the problem we are most interested in is winter pollution, we need to see what are the main drivers of that. We are fortunate that we have several studies which have provided us with some data on how to proceed.

What does the data say?

For starters, PM levels tend to be significantly higher in winter than in the summer.

Secondly and as mentioned earlier, the main contributors to PM pollution differ by season. In the summer, road and construction dust play a big role. The contribution of biomass burning tends to be about three times higher in the winter than in the summer, and is the single largest cause of winter PM pollution. This is not to say the role played by transportation is a small one. Indeed, emissions from diesel and petrol vehicles and diesel generators are large, but fairly constant drivers of pollution throughout the year. This means that while we should certainly address them to bring down year-round pollution, they are not central to reducing the winter pollution spike. Also pertinent to note is the small contribution to pollution of the burning of municipal solid waste, which spikes in the winter as the poorest use these fires to keep warm.

The pollution levels are worsened by another phenomenon: the reduction of vertical mixing of the air in winter.

Normally, temperature decreases as we move higher in the atmosphere until we get to a height where the higher we go, it gets warmer not cooler – this point is called the inversion point. Now consider this: as a packet of warm air containing a lot of pollutants rises, it will keep rising until the inversion point, thereby diluting the concentration of the pollutants in the air. The problem is in Delhi, the inversion heights are about half in winter as they are in summer, so the pollutants are essentially mixed in a substantially smaller volume of air.

How to act (and not to act)

It is understandable that our leaders will want to act (and be seen as acting decisively)– especially when they are in the middle of such a serious problem. However, such actions would be more effective if we considered the data a little more closely and understood the dynamics of the sources a little better.

If only our leaders understood what any parent of a teenager knows: unilateral bans rarely work. Firstly, our implementation of such bans is uneven, and second, bans without alternatives can be deemed unfair, and lastly, bans of less significant causes of winter pollution such as cracker bans, or odd-even schemes can be irritating and worse still, ineffective.

Which means this: If solving the winter air pollution issue of Delhi is your goal, a good place to start the solution would be to ask how can we stop biomass burning?

Predictably, we have started by banning agricultural burning.

As you may have guessed (or read), this has not worked.

One young farmer from Punjab said this: “The farmers are in a state of depression. The government gave us no options of what to do with the straw.”

Bharati Chaturvedi, of Chintan in Delhi, presents an interesting analogy: If you don’t want open defecation, you don’t impose a ban without giving them a toilet –a working toilet that women want to use and where they don’t feel that they will be raped or molested. If you don’t want farmers to burn, give them an option.”

Farmers are protesting because they see the straw as a waste that prevents them sowing the winter crop, and the easiest (and cheapest) way to get rid of it is to burn it.

So, the farmers burn.


Figure 2: Farmer burning field in Punjab (Picture from The Hindu)

And the citizens of Delhi and much of the Indo-Gangetic plains suffer.

Waste as a Resource

Contrast this with what happens inside a cotton spinning mill.

Since I help manage one of these, I can tell you that, surviving in a cyclical, low profit industry, management of waste is central to a factory’s profitability. If you were to take a walk on our shop floor, you would see the “waste” from each process collected, stored separately, weighed and later sold. Records are meticulous, and we understand what machine generates how much of what type of waste in each shift. Our mill is not special – almost every mill in the cotton spinning industry will do so. We do so, not because we are a neurotic lot, but because we make money by doing this. The prices we get more than compensate us for the effort of collection, storage, management and transport. This is because this waste has spawned an entire industry – called open end spinning – employing thousands and probably led to the yarn that went into your favourite pair of jeans.

There it is – the power of treating “waste” as a resource.

The question then becomes, how can we get the farmers to look at their waste as a resource – something that can get them returns and thus stop them from burning it?

Next time, we will take a deep dive into the fields of Punjab and the start-ups in Bangalore to see just that.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s