Interesting to have been in the air over the new year eve with nearly clear skies from Central Germany through Northern Switzerland (21:30):

The skies over Germany were constantly exploding with fireworks (looks like stochastic terrestrial illumination from cruising altitude). Didn’t matter whether villages or cities. Meanwhile in Swiss airspace, essentially nothing seen.

#feuerwerksverbot

Sure, my neck of the woods (CH 8002) was crazy at 23:00–01:00, but no emergency services needed to be called, and essentially no noticeable litter was leftover — even in the Quartierstrassen. The Seepromenade could be another story, however.