China's One-Child Policy (1980-2015)

China's one-child policy prevented an estimated 400 million births over 35 years, arguably averting a Malthusian catastrophe. But it also produced forced sterilisations, infanticide (disproportionately of girls), a gender imbalance of 30 million "surplus" men, and an ageing population crisis that now threatens China's economic future. The policy was relaxed to two children in 2016 and three in 2021 — but the demographic damage may be irreversible. This population control measure is more controversial than India's 1975 emergency sterilisation campaign, as it reduced the global birth rate by 0.5% over three decades, according to UN data.