Thanks to the ULEZ (ultra-low emission zone) in London, this is very much already happening — anecdotally (because I can't find any easy numbers right now, everything I can find is from 2020) a huge number of the private and public taxis in London are now hybrid or full electric.

Apparently there are already 5k TX electric taxis out there, which is a good start:

https://levc.com/levc-celebrates-sale-of-5000th-tx-electric-...

https://levc.com/tx-taxi/overview/

Would you say more about the connection between black snot and ICE taxis?

The reason I ask is that I was under the impression people commonly get black snot from the the tube (eg. https://www.reddit.com/r/london/comments/16jjgt/london_why_d... ).

Where I live (UK town) our biggest local taxi firm has an app and an entirely electric fleet. So we're getting there!

Live in central London and usually walk everywhere, never experienced or even heard of black snot. Pretty sure it’s only a thing for the tube-travelling demographic.