It's wild to me how they're strolling through the sewer tunnel, with the voiceover explaining how it was put under ground to shelter people from all the disease carried in it... and they're wading through it, no respirator or any other protection of the sort.
Surprisingly safe given they're neither drinking the effluent nor washing open wounds with it.
The Great British Sewer Project (version one, not the recent and ongoing rebuild) was all about safe water, the disease came from a contaminated water for drinking and washing pump and not from "the Miasma" (unseen spirit forces wafting about in dank air).
The "put underground" part was mainly about isolating waste water from washing and drinking water, reducing the stench in the air was a related benefit of course, but that wasn't the vector of infection.
Just a few minutes into the video, the reporter gets some splashback in his mouth. That direct hit aside -- there are multiple "tributaries" actively dumping waste into the main tunnel. With all this moving liquid, there's bound to be some of it aerosolized into the air, especially in an enclosed space like that.
