Sure, it's not advisable, and a wetsuit is a necessity, but the fact that it's relatively safe proves that a modern canal city can have clean waters.

After all, there was a royal publicity stunt a decade ago[1], part of what's now an annual event[2].

[1]: https://www.hellomagazine.com/royalty/201209109251/princess-...

[2]: https://www.iamexpat.nl/lifestyle/expat-events-festivals/acs...