adonis simo, thank you for your comments!
In one scenario, at least some of the users need to have an app installed on their mobile (the app described in the idea). The app would interface with Spotify and/or other music streaming services/ it would consume their APIs to get user’s preferences and/or latest songs played. The app then would store the anonymized data (location and music preferences/ songs played) in a centralized data store. Having these data available (location +music preferences for a sufficiently large number of users across their most frequently visited places), you can easily discover the most popular/ trending songs/ genres etc. for the particular audience. The business challenge in this, is how to reach the critical mass of users having this app installed. In another scenario, this could be offered by the music streaming service itself — for instance, built-in to Spotify. Happy to provide more info!