A study published in The Lancet estimates that second-hand smoke caused approximately 1.66 million premature deaths in 2023, with over 2.7 billion people — including 767 million children — exposed worldwide. Researchers analysed data from 204 countries spanning 1990 to 2023, finding that women and children bear a disproportionate share of the burden, with children suffering an estimated 5.2 million respiratory infections linked to passive smoking in 2023 alone. The authors are calling on governments to strengthen tobacco controls in public spaces and homes, warning that no safe level of second-hand smoke inhalation exists.