The fireworks celebrate the 10th anniversary of the handover. Every year we celebrate a day with the catchy title of "Hong Kong Special Administrative Region Establishment Day", and there are fireworks; I was too busy taking pictures of people to see whether the 10th anniversary fireworks were better than usual.
What's that? - oh, sorry, I've just discovered that it's the 10th anniversary of the "reunification".
My apologies, sometimes it's hard to keep up. Don't know what I was thinking of, using a familiar term instead of one with approved nuances.