Lead is a cumulative toxin, so scientists consider no blood lead level to be safe. Children under six are the most vulnerable, and even low exposure can lower IQ, shorten attention spans and raise the risk of ADHD and hearing loss. Lead accumulated in the environment from leaded petrol, paint and pipes, and the removal of lead from petrol cut air levels sharply. Leaded paint used until the 1960s still poses a risk in older homes, dust and soil. Global estimates put the economic cost of childhood lead exposure at about US$3.4 trillion a year in lost earnings and productivity.

Hampi is a UNESCO World Heritage Site in Karnataka, India, with more than 1,600 surviving remains spread over 4,100 hectares. It was the capital of the Vijayanagara Empire from 1336 to 1565. Travellers from Persia and Portugal described it as a prosperous, wealthy and grand city with temples, markets and farms along the Tungabhadra River. By 1500 it was estimated to be the world's second-largest city after Beijing, and probably India's richest at the time. In 1565 a coalition of Muslim sultanates defeated the Vijayanagara Empire, its capital was conquered and destroyed, and the city was left in ruins. Hampi remains a religious centre, with the active Virupaksha Temple at its heart.