"Oshii based the setting for Ghost in the Shell on Hong Kong. Oshii commented that his first thought to find an image of the future setting was an Asian city, but finding a suitable cityscape of the future would be impossible. Oshii chose to use the real streets of Hong Kong as his model.[9] He also said that Hong Kong was the perfect subject and theme for the film with its countless signs and the cacophony of sounds.[6] The film's mecha designer Takeuchi Atsushi noted that while the film does not have a chosen setting, it is obviously based on Hong Kong because the city represented the theme of the film, the old and the new which exist in a strange relationship in an age of an information deluge. Before shooting the film, the artists drew sketches that emphasized Hong Kong's chaotic, confusing and overwhelming aspects."
"Oshii based the setting for Ghost in the Shell on Hong Kong. Oshii commented that his first thought to find an image of the future setting was an Asian city, but finding a suitable cityscape of the future would be impossible. Oshii chose to use the real streets of Hong Kong as his model.[9] He also said that Hong Kong was the perfect subject and theme for the film with its countless signs and the cacophony of sounds.[6] The film's mecha designer Takeuchi Atsushi noted that while the film does not have a chosen setting, it is obviously based on Hong Kong because the city represented the theme of the film, the old and the new which exist in a strange relationship in an age of an information deluge. Before shooting the film, the artists drew sketches that emphasized Hong Kong's chaotic, confusing and overwhelming aspects."
https://en.wikipedia.org/wiki/Ghost_in_the_Shell_(1995_film)