Improved sanitation access for children in rural areas may arrest stunting but early-life exposure to high levels of air pollution could play spoilsport in realising these benefits, warn researchers amid calls for strengthening air pollution laws to prioritise health.

Researchers at the Indian Institute of Technology-Delhi, the Indian Statistical Institute Delhi Centre and the University of Texas at Austin explored how early-life exposure to outdoor PM 2.5 impacts child health, measured as height-for-age, in India, in a study.

They found that that exposure of foetuses – in the last trimester of pregnancy – and newborns to PM 2.5 particles is significantly associated with deficits in child height, which has lasting consequences for human capital and potential ramifications for the Indian society and economy.

The authors tapped into population data from the National Family Health Survey 2015-’16 conducted by the Indian government which covered all 640 districts and surveyed nearly 225,000 children of both sexes. This was mapped against satellite data of monthly PM 2.5 level for 15 years, from 2001-2015 for comparison with the month of birth.

The results show that if a five-year-old girl was born in a place where outdoor PM 2.5 was 100 microgram/cubic metre lower than that it was in the place of her birth, she would have been 0.24 cm taller.

“Our results imply that while rural children in India might expect to arrest stunting due to better sanitation access from Swachh Bharat initiative, this benefit might not be realised if they remain exposed to high air pollution which would increase stunting,” study author Sagnik Dey of IIT-Delhi’s Centre for Atmospheric Sciences, told Mongabay.

In the past few years there has been an intense effort to address air pollution in India. Credit: CIAT/Wikimedia Commons

Three child health outcomes, height-for-age which is a measure for stunting, weight-for-age which is a measure for overweight and weight-for-height which is a measure for wasting offer insights into how healthy their adult lives would be.

Dey argued it is extremely important for India to ensure successful implementation of India’s clean fuel programme Pradhan Mantri Ujjwala Yojana, which will not only reduce household air pollution and cause a large improvement in ambient air pollution but also improve child health.

According to an Energy Policy Institute at the University of Chicago study, which developed the Air Quality Life Index, on average, people in India would live 4.3 years longer if the country were to clean its air.

Quoting the Air Quality Life Index data Indian parliamentarian Vandana Chavan recently raised the issue of amending air pollution laws to prioritise health.

In the ongoing Parliament session, Chavan said: “In 1981 India passed the Air (Prevention and Control of Pollution) Act. The law does not once mention protecting health. This makes it far too easy to prioritise interests of polluters over the wellbeing of our people. In contrast, protecting health is the principal objective of nearly all nations that have successfully combatted air pollution. We need to amend our air pollution laws to prioritise the health of our citizens.”

Past studies have looked into air pollution exposure during pregnancy and low birth weight outcome and have found how indoor, or household, air pollution and passive smoking impact stunting and other child health outcomes in various low and middle-income countries including Bangladesh.

“To our knowledge, this is the first study to directly estimate the impact of early-life exposure to ambient PM 2.5 on child height-for-age at the range of exposures found in India,” said Dey.

The Indian government unveiled its long-awaited National Clean Air Programme earlier this year aiming at 20%-30% reduction of particulate matter concentration over the next five years, with an overall goal of mitigating air pollution and improving air quality in the country, which has some of the world’s most polluted cities. The programme takes into consideration city-specific action plans for 102 non-attainment cities identified for implementing mitigation actions.

The researchers write in the study that although policy conversations often focus on India’s capital New Delhi – and, to a lesser extent, other big cities – we find effects throughout India and on both rural and urban children, suggesting that the policy challenges are broader than they seem.

Children in rural areas

The study underscored the rural-urban divide in air pollution and sanitation access, the seasonal interventions to reduce air pollution and additional vulnerability for children born to shorter mothers.

Although, in general, children in rural areas in India are shorter than their urban counterparts – because of poor sanitation and nutrition – when pollution level increases, rate of decrease in height-for-age is more-or-less similar in urban and rural children.

“This shows that rural children face a double whammy as they are more vulnerable to the combined effects,” said Dey.

The maximum effect of toxic air particles – leading to height decline – is between November to January when the pollution level in India reaches its peak. So clearly, reducing pollution in this critical period is expected to have a much larger benefit at the population level, said Dey.

“When we sort the data as per mother’s height, we observe shorter mothers have shorter children,” he said. “But pollution affects everyone in a similar manner. So children born to shorter mothers would be more vulnerable if born in a polluted environment.”

Population researcher and co-author Dean Spears of Department of Economics and Population Research Center, the University of Texas at Austin, who has explored the Asian enigma as in why Indian children – mainly in rural India – are shorter than poor African children, drove home the point that the child health impacts due to air pollution in India need attention because the problem is getting worse, not better.

“When we see air pollution impacting children’s growth, that tells us that it does not merely make many people ill and kill some people, it also harms the development of the tens of millions of children exposed to it – keeping them from growing to their full health, physical, cognitive, and economic potentials,” said Spears who is also a visiting researcher at Indian Statistical Institute, Delhi Centre. “Air pollution is not as big as a factor in the height of Indian children as other challenges such as maternal nutrition or open defecation, but air pollution is special because it is getting worse, not better.”

Of the total deaths in 2017 in India, 1.24 million deaths, equivalent to 12.5% of total mortalities, could be attributed to air pollution, according to an India State-Level Disease Burden Initiative report, published in The Lancet in December.

Recounting her own experience as a mother to a seven-year-old son who has experienced the effects of air pollution exposure, population researcher Nandita Saikia said the Indian government has failed to elevate the focus on the issue to a level that reflects the gravity of the situation, especially pertaining to the health of citizens.

“My son used to suffer frequently from cough and other symptoms that were linked to Delhi’s polluted air,” Saikia, assistant professor in population studies at Jawaharlal Nehru University’s School of Sciences, told Mongabay. “But after we moved to Vienna, he hardly experienced those symptoms. Additionally, because of the cleaner air children could play and exercise outside which is not possible in polluted cities like Delhi. Air pollution is keeping children from growing up to their full potential which can have consequences for the country’s economic development. Stringent regulations and enforcement are what we require before it is too late.”

This article first appeared on Mongabay.