In the US, crime basically kept increasing until the 1990s and have been on a downward trend ever since. If you've fallen for the modern crime panic, it's completely manufactured. Look at any graph that goes back 40+ years and then tell me what the trend is.

The reason for this is hotly debated.

One theory is that it coincides with being 18 years or so after abortion was legalized [1]. The argument is that not forcing people to be parents who don't want to be and aren't equipped to be as well as this skewing to lower socioeconomic status. The link between poverty and crime has been well-established going back to Ancient Greece. In some ways, this is an uncomfortable argument because it's basically eugenics. In support of this, abortion access varied state-to-state by up to several years and the trends tend to follow that.

But this is a US-specific argument and I believe the trend was present in other countries.

The second big argument is removing lead from gasoline (in particular, but also water because of lead pipes) [2].

I really wonder what societal problems and public health incidents in the future will come down to micro-plastics.

[1]: https://en.wikipedia.org/wiki/Legalized_abortion_and_crime_e...

[2]: https://en.wikipedia.org/wiki/Lead%E2%80%93crime_hypothesis