Thanks to everyone who alerted me to this incident.
By analysing online images I think I've found the cause, and want to assure the people affected that despite the huge discomfort caused, they will not suffer permanent eye damage as a result of being at the event.
It's bizarre that both the recent events involving public exposure to high level UVC wavelengths were in Hong Kong. I wonder if there's a connection.
https://www.youtube.com/watch?v=6DlfLthx89E
Mariah Carey
2023-11-08 04:37:36 +0000 UTC