The water is often unsafe, killing more than 3 million people a year, mostly children. And pollution from the fuelwood and other biomass – which 2.5 billion people have to use because they lack modern forms of energy – disproportionately kills women and children, who spend most time in the home.

Women, who tend to carry more fat, are also more vulnerable to the toxic chemicals that build up in it, and so are their unborn babies. In countries as different as the United States and the Sudan increased neonatal deaths have been found among the children of women farmers exposed to pesticides. High levels of dioxins and other hazardous chemicals have been found in breast milk in a wide variety of countries, while women exposed to polychlorinated biphenyls (PCBs) around North America’s Great Lakes have given birth to children with delayed motor development and dramatically lower intelligence.

Yet women are often also at the forefront of the fights to conserve health and the environment. They have led the Chipko movement against the felling of forests in northern India and similarly are campaigning against chemical-intensive agriculture across the subcontinent. The soil in women’s plots in Ghana has been found to retain its fertility longer than the soil in men’s ones, while half of all the United Kingdom’s organic farmers are female, ten times the proportion in the country’s agriculture as a whole.

Geoffrey Lean