Thousands or maybe millions of dead and dying fish in Tejo / Tagus river at Vila Velha de Rodão and other locations such as Nisa and Mação, but also Vila Franca de Xira near Lisbon.
Locals are blaming a celulose factory from CELTEJO that processes the prevalent eucaliptus into paper and others, an industry / culture present in Portugal, it might also be from agriculture chemicals.
The police has been called to the scene without results. Until it gets properly analyzed there is no way of telling for sure but there is a high concentration near this factory area.
PT article:
https://www.jn.pt/local/noticias/portalegre/nisa/interior/milhares-de-peixes-mortos-no-tejo-devido-a-poluicao-8892729.html
Special thanks to Arlindo Marques and ProTejo for denouncing this for a long time