Because your entire country is suffering from generations of developmental issues caused by lead poisoning.
https://www.theguardian.com/us-news/2021/mar/31/americas-tap-water-samples-forever-chemicals
"Exposure to lead can have a wide range of effects on a child's development and behavior. Even when exposed to small amounts of lead levels, children may appear inattentive, hyperactive, and irritable. Children with greater lead levels may also have problems with learning and reading, delayed growth, and hearing loss. At high levels, lead can cause permanent brain damage and even death"