1. A "fog disaster" in Maastal near Lüttich claims 100 lives.

  2. The first patent for production of synthetic fibres is granted. Under the Nazi policy of self-sufficiency, the industry expands greatly in the 1930s.

  3. World Animal Day was started in 1931 at a convention of ecologists in Florence as a way of highlighting the plight of endangered species. Since then it has grown to encompass all kinds of animal life and is widely celebrated in countries throughout the world. October 4 was chosen as World Animal Day as it is the Feast Day of St Francis of Assisi, the patron saint of animals.

  4. Sewage containing mercury is released by Chisso's chemicals works into Minimata Bay in Japan. The mercury accumulates in sea creatures, leading eventually to mercury poisoning in the population.

  5. Otto Hahn and Fritz Straßmann discover nuclear fission.

  6. Discovery of insecticide DDT. P. Müller receives the Nobel Prize in 1948. DDT has been banned in Germany since 1972.