I'd sooner clean it up myself than call the cops. Something violent has to be happening for me to think the risk of violence the police pose is outweighed by the crime.
I use my phone to document this and report it to authorities. No mercy. This country has free disposal plants where recycling and disposal are managed to reduce environmental impact.
I think I'd record it on my phone without them seeing and report it to the police. Try to get their license plate number if the phone didn't get it. F\cking assholes. Of course, I'm not really sure it matters whether the trash gets dumped in an official Earth-raping area or an unofficial one; there's that.
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