Associations of greenness surrounding schools with blood pressure and hypertension: A nationwide cross-sectional study of 61,229 children and adolescents in China

•This is one of the few studies to assess greenness and blood pressure in children.•We explored this topic in a large Chinese children population (n = 61,229).•Higher greenness levels were associated with lower blood pressure levels.•Stronger associations were observed in boys, being older, or living in cities.