"Dump no waste drains to river" --> companies(/people) were dumping waste drains in the rivers, affecting the fish (see same sign). This action seems to seek attention to reduce this practice.
Only because apparently there is an industrial area called "Helhoek" ("A corner of the hell" in Dutch)
I've been within 1 kilometer of there! (and passed literally right next to it on the train ) "Oops" And to make 607 happy:
I didn't even realise the 0 before it... I did realise that there is another, different, number in the picture... Opening this picture lead to downloading it... to imgur it goes, then.
I've just realised that it is quite interesting how the UK and Ireland are very much pro double decker buses (I wouldn't be surprised if they have more dpuble deckers than single deckers), while at the same they are very anti double decker trains (as in there are literally none). Interesting. --- This is a gas fuel tank from a 1955-1957 Chevy Chevrolet.