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Meeting India’s clean air and energy goals could substantially reduce anaemia prevalence among women of reproductive age, according to a study that links exposure to fine particulate matter (PM2.5) to a high anaemia prevalence among women. The study unpacks links of specific PM2.5 pollutants to the common blood disorder.

The evidence comes against the backdrop of the latest review by the Lancet Commission on pollution and health, which underscores that “we are going backwards,” on actions to control pollution and prevent pollution-related disease. The review also emphasises the links between pollution, climate change and biodiversity loss.

In India, where the Centre has consistently sought more indigenous evidence on pollution and health impacts to justify the delay in action, scientists led by the Indian Institute of Technology-Delhi, used multiple datasets, including the National Family Health Survey and satellite data to link pollution and health. Their findings show that for every ten microgram/metre cube increase in ambient PM2.5 exposure, the average anaemia prevalence among women increases by 7.23%.

What is PM2.5?

PM2.5 refers to fine, inhalable particles or particulate matter with diameters that are generally 2.5 micrometers and smaller. For comparison, the average human hair is about 30 times larger in diameter than the largest fine particle. This particulate matter contains a mix of solid particles and liquid droplets and can cause air pollution-related health problems.

The study found that anaemia prevalence among women of reproductive age in India was 53.1% – one of the highest percentages globally, with urban India having slightly fewer cases compared to rural. Anaemia prevalence among women of reproductive age (15 to 49 years of age) will fall from 53% to 39.5% if India’s clean air targets are met, taking 186 districts below the national target of anaemia reduction to 35% for women of reproductive age.

The transition to clean energy could speed up India’s progress in its anaemia-free mission targets. “While malnutrition is the biggest risk factor for anaemia, air pollution is still a risk factor. Particulate matter composition, matters. We are trying to generate cumulative evidence to be able to comment which type of particulate matter is more toxic, so when you try to control them, you prioritise more toxic pollutants. Because the composition is linked to sources, ultimately at the policy level, you will have to target those sources,” Sagnik Dey at IIT-Delhi told Mongabay-India.

A layer of smog covers Mumbai’s skyline. Identifying health-relevant PM2.5 sources in the air to guide control measures is essential for public health and environmental policy. Credit: Christian Haugen/Flickr.

Building evidence

However, Dey adds a disclaimer. “Just based on one health outcome, such as anaemia reduction, you cannot synthesise (sector-based targets). We aim to look at multiple health outcomes so you can decide on air pollution reduction targets based on multiple outcomes.”

In a 2021 paper, Dey and colleagues suggested that ambient PM2.5 exposure could be linked to anaemia in Indian children, batting for additional research on the underlying biologic mechanisms.

“It is important to understand how PM2.5 causes anaemia and its other well-documented adverse effects. Studies of the differential effects of PM components are an important part of that effort, but from a public health and environmental policy standpoint the goal of research should be to identify health-relevant PM2.5 sources to guide control measures rather than to identify biologic ‘magic bullet(s)’,” said study co-author Aaron J Cohen, Consulting Principal Scientist at Health Effects Institute.

“PM2.5 is a complex mixture (and total ambient air pollution even more so) whose constituents and characteristics and health impacts vary spatially and temporally among and within countries. This variation reflects the different sources that contribute emissions to the mixture,” adds Cohen, a co-author also on the Lancet review.

More research

There is a pressing need for research in low- and middle-income countries, which account for the lion’s share of the enormous estimated global burden of disease attributed to air pollution exposure, stressed Cohen. “Although this situation is improving, due to research by Sagnik’s group and others in India, China and Africa, the progress is limited in many locations by lack of air pollution monitoring data and incomplete vital registration of deaths,” he adds.

The Indian government has maintained that “no conclusive data is available in the country to establish direct correlation of death/disease exclusively due to air pollution.”

However, considerable global evidence links exposure to PM2.5 and other pollutants to severe adverse health effects, including deaths from communicable and non-communicable diseases. “Governments should assume that these effects are occurring in their jurisdictions even in the absence of local health studies,” notes Cohen.

Rather than insisting that action to reduce exposure be deferred until studies can be replicated locally, Cohen says, efforts to reduce emissions from major sources should “begin while at the same time increasing the monitoring of air pollution levels and population exposure” and working with health authorities and local researchers to measure adverse health effects and lay the basis for evaluating progress in the future.

In a commentary published this August, on the study by Dey and collaborators, scientists Ajay Pillarisetti and Kalpana Balakrishnan, write that “there is no shortage of reasons to act to reduce air pollution levels in India and beyond. For many years, policymakers in India have sought more evidence generated in India to motivate that action and, in recent years, that desire has increasingly been fulfilled. Owing partially to the growth of this high-quality Indian evidence base, the National Clean Air Programme was launched in 2019 to reduce air pollution exposures across the country.”

The air pollution-anaemia in women study, they write, “contributes more high-quality evidence” and “justifies acting now to reduce the large burden of air pollution exposure and related disease currently experienced across the Indian sub-continent.”

A planetary threat

“Linking research and action on climate and air pollution is critical because reducing and ultimately eliminating the burning of fossil fuels is key to both,” stressed study co-author Aaron Cohen, Consulting Principal Scientist at Health Effects Institute.

Considering pollution, in general, as a “planetary threat”, The Lancet review too discusses a “large-scale, rapid transition away from all fossil fuels to clean, renewable energy” as an effective strategy to prevent pollution while also slowing down climate change.

The Lancet review finds that pollution remains responsible for approximately nine million deaths annually, corresponding to one in six deaths worldwide. Reductions have occurred in the deaths attributable to the types of pollution associated with extreme poverty. However, it states that these reductions in deaths from household air and water pollution are offset by increased deaths attributable to ambient air pollution and toxic chemical pollution (such as lead).

Deaths from these modern pollution risk factors (ambient air pollution, lead pollution, and chemical pollution), which are the unintended consequence of industrialisation and urbanisation, have risen by 7% since 2015 and by over 66% since 2000.

At a garbage dumping ground in New Delhi in May. Credit: Reuters.

Despite ongoing efforts by United Nations agencies, committed groups, committed individuals, and some national governments (mostly in high-income countries), little real progress against pollution can be identified overall, particularly in the low-income and middle-income countries, “where pollution is most severe.”

Underscoring that pollution, climate change, and biodiversity loss are closely linked, the reviewers say successful control of these conjoined threats requires a globally supported, formal science–policy interface to inform intervention, influence research, and guide funding.

Human, economic losses

In terms of loss of human capital for selected locations, the review finds that in 2000, output losses due to traditional pollution (household air pollution from solid fuels and unsafe water, sanitation, and hand washing) were 6·4% of GDP in Ethiopia, 5·2% of the gross domestic product in Nigeria, and 3·2% of GDP in India. Human capital refers to human quality or value, or skillsets that can improve economic output and productivity.

By 2019, death rates due to traditional pollution were a third of the death rate in 2000 in Ethiopia and Nigeria, and less than half of the death rate in 2000 in India. “Consequently, pollution-related economic losses as a proportion of GDP fell substantially. However, the review notes that the economic losses due to traditional pollution stand at approximately 1% of GDP in India and 2% of GDP in Ethiopia.

Lost economic output as a proportion of country GDP due to deaths from modern and traditional pollution in 2000 and 2019. Credit: The Lancet review paper Pollution and health: a progress update.

Economic losses due to modern forms of pollution have increased as a proportion of GDP between 2000 and 2019 in India, China and Nigeria, and are now conservatively estimated to amount to approximately 1·0% of GDP in each of these countries. The full economic losses, if the full health impacts of pollution were to be counted and the effects of pollution on informal sectors and environmental damage were to be fully detailed, are “likely to be greater,” according to the review.

“By contrast, economic losses due to modern forms of pollution have fallen as a proportion of GDP in the USA and EU15 countries. The reduction of economic losses in these countries reflects pollution control, the outsourcing of polluting industries, and reductions in death rates,” the review states.

This article was first published on Mongabay.