Hardcore pro-democracy protesters left a trail of havoc and destruction across Hong Kong on Sunday, marching in defiance of a police ban and targeting government buildings and subway stations with vandalism.

The day’s violence, which began with masked demonstrators hurling petrol bombs and smashing windows at Admiralty and Wan Chai stations marked the 15th straight weekend that protests have gripped the city and raised questions over how the Asian financial hub’s future will be shaped.

The economic effects of the three-month crisis were brought into sharp focus on Sunday when Hong Kong International Airport released figures showing it had seen its biggest monthly drop in passengers for a decade in August as the protests prompted tourist and business visitors to cancel trips.