^Actually that would be Hong Kong, which if you stacked up all the highrises in each city, would be 3x that of NYC:
https://supermouse.blog/2016/07/18/t...highrise-city/.
However, Shanghai, Seoul, Shenzhen and Sao Paulo which are woefully undercounted, are rumoured to have more highrises (not skyscrapers) than HK.
Overall though, it's still Shenzhen, with the gap ever increasing as the world's fastest growing city (81 skyscrapers u/c, whose supertalls may triple this decade, with 8 currently u/c).: