> Defusing mostly concern unexploded ordinance from WW2 and there is at most one major event a year in Europe as a whole. It is certainly not "constantly blocking business for days in major cities".

If you mean “constantly” in the sense of “every day” the yes, it’s not constantly. It’s however, constant enough to be reminded constantly - multiple times every year in Berlin alone. Last one I can recall was Feb 24th this year in Spandau. In 1994 one exploded when it was excavated https://www.gettyimages.de/detail/nachrichtenfoto/explosion-...

In 2019 a major shipping channel in the region was closed for at least 2 month https://m.maz-online.de/Lokales/Oberhavel/Oranienburg/Oranie...

It’s so common here that it’s not big news unless the bomb is exceptionally large.