Is lead exposure making South Asia more violent?

The region has one of the world’s heaviest lead burdens. But the science linking lead to aggression and violent crime is far more complicated.

Lead is an oddly discreet villain.

It does not announce itself with smoke. It has no sinister smell. You cannot look at a plate of rice, a child’s toy or a shiny aluminium cooking pot and say, “Ah yes, neurotoxin.” It can sit quietly in soil, dust, paint, spices, cookware and cosmetics. It can travel home from a battery recycling workshop on somebody’s clothes. And once it gets into a child’s body, it can interfere with the one organ we spend decades trying to develop and approximately five minutes destroying on social media: the brain.

For Bangladesh, this is not some abstract environmental health concern discussed in conference rooms and policy papers. The latest nationally representative data are fairly terrifying.

The Bangladesh Multiple Indicator Cluster Survey 2025, conducted by the Bangladesh Bureau of Statistics with UNICEF, tested around 11,000 children aged 12–59 months. It found that 38.4 per cent had blood lead levels of at least 5 micrograms per decilitre (µg/dL). The mean was 5.21 µg/dL. Among pregnant women, 7.5 per cent crossed that same benchmark.

A necessary clarification here: 5 µg/dL is not a magical line below which everything is fine. The World Health Organization says there is no known safe level of lead exposure, and adverse effects in children have been observed at blood concentrations as low as 3.5 µg/dL. WHO estimates that lead exposure contributed to more than 3.5 million deaths worldwide in 2023, overwhelmingly through cardiovascular effects.

So yes, Bangladesh has a lead problem.

Back in 2020, UNICEF and Pure Earth estimated that around 800 million children worldwide had blood lead levels above 5 µg/dL. Nearly half lived in South Asia. India alone accounted for an estimated 275.6 million children; Pakistan for 41.1 million; and Bangladesh for 35.5 million. At the time, Bangladesh ranked fourth in the world by the number of affected children.
 

Those figures were modelled estimates and are now several years old, so they should be read with appropriate caution.

A comprehensive review published in August this year, covering Bangladesh, Nepal, Sri Lanka, India and Pakistan, reached a similarly grim conclusion: blood lead concentrations across South Asia frequently exceeded the US CDC reference value of 3.5 µg/dL. Importantly, the researchers found that since leaded petrol disappeared, the villains have diversified. Food, spices, vegetables, rice, contaminated air and consumer products now form a messy web of exposure.

India remains staggering simply because of its scale. A 2025 systematic review of 51 studies estimated a pooled mean blood lead level of 10.4 µg/dL among Indian children. Even children without a known high-risk exposure averaged 8.71 µg/dL. The authors were careful to note considerable heterogeneity and generally weak underlying evidence, but there is no plausible reading of those numbers in which everything is hunky-dory.

Pakistan is still assembling its national picture. In May 2026, a government-UNICEF study of more than 2,100 toddlers living in high-risk areas of seven cities found elevated lead exposure in roughly four out of ten children; in Hattar, Haripur, the figure reached 88 per cent. UNICEF says modelling suggests that as many as eight in ten Pakistani children could be affected, among the highest proportions globally, but a nationally representative survey is still needed.

If there was ever a case for South Asian regional cooperation that did not involve border disputes or arguments over water-sharing, this may be it.

How did lead get everywhere?

For decades, the obvious source was petrol. South Asian countries eventually removed lead from fuel, producing enormous public health gains. Unfortunately, lead did not receive the memo that its services were no longer required.

Bangladesh is believed to have had more than 1,100 informal or illegal used lead-acid battery recycling operations, according to a UNEP assessment. Backyard smelting and crude recycling can contaminate surrounding soil, dust and air, while workers can carry lead home to their families.

Researchers also discovered that some Bangladeshi turmeric processors were adding lead chromate, an industrial yellow pigment, to make inferior turmeric look brighter. A 2019 investigation found evidence of the practice in seven of nine major turmeric-producing districts, with some turmeric exceeding the national lead limit by up to 500 times. Isotope analysis linked the adulterated spice to lead in pregnant women’s blood.
 

Lead has also turned up in paints, ceramics, toys, cosmetics and recycled-metal cookware. A Pure Earth market survey in Bangladesh detected it across nine categories of consumer products. South Asian surma and kajal have produced spectacularly high readings in some international investigations, while recent research has shown that lead can leach from recycled aluminium and brass cookware made in the region.

Lead damages the developing brain. That much is not controversial.

Childhood exposure has been associated with lower intelligence, poorer attention, weaker working memory and executive function, behavioural difficulties and impaired educational performance. MRI research following children into adulthood has found that higher childhood lead levels are associated with reduced grey matter volume in parts of the prefrontal cortex and anterior cingulate cortex, areas involved in decision-making, mood regulation and executive control.

So, what happens when millions of children grow up with a neurotoxin capable of affecting impulse control and behaviour circulating in their bodies?

This is where the conversation gets fascinating. It is also where we need to put down the sensational headline and behave like adults.

Higher childhood lead exposure was associated with higher arrest rates, including arrests for violent crimes in some analyses. Another strand of research noted that violent crime in several wealthy countries fell roughly a generation after leaded petrol was phased out.

Lead exposure during childhood can cause lasting damage to the developing brain, affecting cognitive abilities, behavioural development and learning, with consequences that may extend well into adulthood.

Informal recycling of lead-acid batteries, including those used in electric three-wheelers, is a major source of lead contamination in Bangladesh, putting workers and surrounding communities at risk. Photo: Rashed Shumon

At Kathgora, north of Dhaka, where informal battery recyclers had left heavily contaminated land behind, a clean-up led to an average 42 per cent reduction in children’s blood lead levels after about 18 months.

 These are not tiny victories. They tell us something unfashionable: regulation works, enforcement works, and cleaning contaminated land works. Making producers stop putting poison into food works.