Air pollution poses hidden threat to women's reproductive health globally

Riya Gupta is pregnant in Delhi, one of the world's most densely populated cities, and she carries two sources of worry. The first—Covid-19 and its potential effects on fetal development—dominates headlines. The second, she has come to understand, may pose a quieter but more persistent threat: the air she breathes every day. As someone who works in public health communications, Gupta has begun reading research linking air pollution in Delhi specifically to lower birth weights and increased risk of premature delivery. She is in her second trimester, and the findings unsettle her. She calls air pollution "the slow killer," distinguishing it from the acute threat of pandemic illness.

Delhi holds the distinction of being the world's most polluted capital, according to real-time air quality data collected by IQAir, a Swiss monitoring company. But Gupta's anxiety reflects a problem that extends far beyond her city or even her country. Nearly 99 percent of the global population breathes air that exceeds the World Health Organisation's safety thresholds. The burden falls heaviest on poor and developing nations, where the vast majority of the seven million annual deaths linked to air pollution occur each year. Yet public health officials have historically trained their attention on respiratory disease and impacts on young children, leaving the connection between air quality and women's reproductive outcomes largely unexamined and largely absent from policy conversations.

The scientific evidence, however, is accumulating. Pallavi Pant, a senior scientist at the Boston-based Health Effects Institute, describes a growing body of research documenting that pregnancy exposure to air pollution correlates with preeclampsia, miscarriage, gestational diabetes, high blood pressure, preterm birth, low birth weight, and in some cases stillbirth. Some studies have also found associations between air pollution and reduced fertility rates or depression in pregnant women. The mechanisms are not fully understood, but the pattern is clear: pollution harms pregnancy.

The exposure women face is not limited to outdoor air. In densely populated regions of South Asia, women bear a disproportionate burden from indoor air pollution because they typically assume primary responsibility for cooking, and firewood remains a dominant fuel source in many households. India alone records an estimated 0.61 million deaths annually attributable to indoor air pollution, though the data has not been broken down by gender. Beyond the direct health cost, the burden extends further: women often spend hours collecting fuelwood, time that could otherwise go toward work or rest. When indoor pollution also sickens young children—as it frequently does—women shoulder the dual responsibility of managing their own health while caring for ill dependents.

The geographic concentration of this crisis is stark. In 2021, eighteen of the world's twenty most polluted cities lay scattered across the Indo-Gangetic plain spanning India and Pakistan. Four of the ten worst countries for air pollution globally—Bangladesh, Pakistan, India, and Nepal—sit in South Asia. Across this region, most people inhale air polluted at levels dozens of times higher than WHO safety limits. The State of the Global Air report released in March 2020 found that air quality in India and Nepal had shown virtually no improvement over the preceding decade. Modeling studies suggest that improving air quality in South Asia alone could prevent seven percent of pregnancy losses in the region. The same particulate pollutants driving this reproductive harm also trap heat in the atmosphere, meaning that solutions to clean the air would simultaneously advance climate goals.

Yet policy responses have largely ignored gender dimensions of exposure. Tanushree Ganguly, an air quality researcher at the Council of Energy, Environment and Water, examined 102 air cleaning plans across Indian cities and found that while India's National Clean Air Programme acknowledges indoor pollution's impact on women and children, city-level implementation plans do not explicitly address gender. Azra Khan, a programme manager at the think tank WRI-India, points out that women face elevated outdoor exposure as well: a pilot study in Bhopal found women more likely to walk to work, thereby breathing higher concentrations of pollution during daily commutes. Women in low-wage occupations—street sweeping, construction, street vending—encounter particularly severe exposure. Yet most available data focuses narrowly on household pollution, leaving a gap in understanding how air quality affects women's health across their full lives and work.

The few initiatives targeting women have achieved limited results. The Pradhan Mantri Ujjwala Yojana, a flagship government program, aims to help rural and poor households transition to cleaner cooking fuels by distributing cooking gas cylinders, but uptake has been uneven and gaps persist. Localized interventions like smog towers erected in Delhi have failed to meaningfully reduce pollution. Large-scale renewable energy investments remain promising but have not yet significantly lowered pollution levels, as India continues to rely heavily on coal-fired thermal power plants. Individual measures—air purifiers installed indoors—offer some protection, but they cannot shield people from outdoor exposure. Gupta, who grew up in Delhi and has installed purifiers in her home, acknowledges the limits of personal action. "I have to travel to work," she said. "No matter what I do, I am exposed."