A total of 1,974 cities worldwide recorded growth in GDP per capita alongside declines in nitrogen dioxide (NO₂) concentrations between 2019 and 2024. Of these, 719 were in China, accounting for more than one-third of the total, Vice Minister of Ecology and Environment Xu Bijiu said at a press conference on Thursday, citing a study published in "Nature Cities" in May 2026. The study analyzed cities worldwide with populations of more than 100,000.