[konart]

>Located less than 200 kilometers south of Moscow, the industrial city of Tula is home to around 549,992 people. And about a fifth of them have no access to centralized sewage systems.

I really doubt about 1/5 but yes, sure, some parts of Tula look like this: https://st05.realtymag.ru/1911/2023-03-31/0/2101217236877371... basically a village with no connection to Tula's centralized sewage system.

>From a public health standpoint, human waste reaching rivers tend not to be good.

It doesn't in most cases. It goes into a hole. By the time it reaches river via ground waters there is literally no problem.