As a German, I feel a bit uncomfortable with this sign on a train. But it reads: "We will not be involved with illegal diesel fuel!!"
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RE: https://chaos.social/@josch/115886739979458949
Interesting to see this in the Tokyo metro:
a poster, warning people to not buy oil which is watered down or untaxed.
Some people use it for heating here, even more in Touhoku and Hokkaido.
The city has setup a full campaign to fight this: https://www.tax.metro.tokyo.lg.jp/kazei/automobiles/oil/200009f .