Devangshu Datta: The poisoned air we breathe

Air pollution is estimated to have cost Delhi and Mumbai around Rs 70,000 crore in 2015

The education minister of Rajasthan recently made the absurd assertion that cows exhale oxygen. In truth, collecting “cow exhalation” in an oxygen cylinder and breathing it in would be as efficient a means of committing suicide as inhaling exhaust gases from a car. Cows exhale carbon dioxide like other mammals. Bovine species also contribute to global warming by emitting methane (via wind and burps).

Methane (CH4) is one of the multitude of gases that can be harmful. A cow’s methane emissions generate the equivalent of four tonnes of atmospheric carbon dioxide (CO2) a year. India has a huge livestock population and the long-term consequences of those emissions may be serious. 

But particulate pollution is more immediately lethal. A new study in the Environmental Science and Pollution Research journal estimates that particulate pollution contributed to at least 80,665 premature deaths of adults in Mumbai and Delhi in 2015. This is over twice as high as the total number of premature deaths (39,007) attributed to similar particulate matter in 1995. Mortalities in Delhi rose from 19,716 in 1995 to 48,651 in 2015, while Mumbai saw deaths rise from 19,291 (1995) to 32,014.

In economic terms, air pollution is estimated to have cost the two cities around $10.66 billion (approximately Rs 70,000 crore) in 2015, or about one per cent of India’s gross domestic product. The estimated total cost (using constant USD prices of 2005) increased from $2.680 billion to $4.269 billion for Mumbai and from $2.7 billion to $6.394 billion for Delhi, from 1995 to 2015. 

The study focused on two specific sizes of particles, the PM10 (particulate matter of 10 microns) and the PM2.5 (particulate matter of 2.5 microns). The major causes of death were premature cerebrovascular disease, ischemic heart disease, and chronic obstructive pulmonary disease, which contributed about 35.3 per cent, 33.3 per cent, and 22.9 per cent, respectively to attributable mortalities. Given that there are many other particles in the atmosphere, those numbers are almost certainly underestimates. They don’t capture the full negative impact of air pollution in those two cities. 

Air pollution was responsible for 23 million cases of restricted activity days (RAD), when productivity declined in Mumbai in 2015 and led to 64,037 emergency room visits in 2015 by sufferers of respiratory ailments, which was up by 35.4 per cent from 1995. Delhi was worse, with 29 million cases of RAD and 120,000 emergency room visits in 2015. 

Other interesting data include the concept of disability-adjusted life years (DALY). This is an estimate of years lost due to various illnesses. This measure for illnesses caused by air pollution doubled in Delhi between 1995 and 2015 from 340,000 to 750,000 DALYs. In Mumbai, it rose from 340,000 to 510,000 DALYs. Chronic bronchitis and mortality shared about 95 per cent of the total DALYs.

The lead author of the study is research scholar Kamal Jyoti Maji of IIT Bombay, along with professor Anil Dikshit of the same institute and Ashok Deshpande from the Berkeley Initiative in Soft Computing, USA. The researchers hope that the results would help policymakers undertake cost-benefit analyses of air pollution management programmes in Mumbai and Delhi. One of the more depressing conclusions is that PM10 levels would have to decline by 44 per cent in Mumbai and 67 per cent in Delhi in order to simply ensure that the health situation does not get worse.

Policymakers are close to desperation. Delhi tried the “odd-even” formula but that didn’t help much. Mumbai has started experimenting with outdoor air-purification units placed at busy traffic junctions. The so-called Wind Augmentation and Purifying Units have been developed by IIT-Bombay and the National Environmen-tal Engineering Research Institute. These have been installed at Sion, Kalanagar junction, Ghatkopar, Bhandup, etc. It is hoped that this will reduce local pollution considerably, by 40 to 60 per cent.

Delhi is setting up an experiment involving decommissioned jet engines. Researchers hope that jet engines placed strategically near thermal power plants can blast PM straight up, by creating a sort of virtual chimney. The emissions from a 1,000-megawatt coal-thermal plant are equivalent to emissions from roughly 500,000 cars. If this experiment works, it could be used to reduce smog from thermal plants. 

Instead of making absurd assertions about cow-breath, policymakers need to focus on the real and present dangers of atmospheric pollution. That study is frightening in what it reveals about the damage caused by pollution in India’s two largest, most polluted cities. There are plenty of other, highly polluted Indian cities as well. The mind boggles about the scale of damage across the entire country.