Where in Wikipedia? The Wikipedia page at https://en.wikipedia.org/wiki/List_of_metropolitan_areas_by_population says Shenzhen, Lagos, New York City, Osaka, Wuhan, Chengdu, Dhaka, Chongqing, Tianjin, Tehran, Istanbul, London, and Hangzhou are bigger than Buenos Aires. The Wikipedia page at https://en.wikipedia.org/wiki/List_of_agglomerations_by_population says New York, Osaka, Dhaka, and Lagos are bigger than Buenos Aires.
https://en.wikipedia.org/wiki/List_of_urban_areas_by_population
which starts Tokyo, Jakarta, Delhi, Manila, NYC