I wouldn't call it slang, it is the common way to refer to the act in media, and the government uses it, e.g: https://www.gov.uk/report-flytipping https://www.g

I wouldn't call it slang, it is the common way to refer to the act in media, and the government uses it, e.g: https://www.gov.uk/report-flytipping https://www.gov.uk/report-flytipping (they do define it, however, as you say, it would be unclear if you aren't familiar).