M. Sanjayan

It’s not totally clear what caused these mountains of foamy buildup on a Nairobi creek, but Nature Conservancy scientist M. Sanjayan, who observed the phenomenon, suspects a combination of fertilizer runoff, sanitation waste, industrial effluent, and detergent. In short, it’s even grosser than it looks, by kind of a long shot.

This creek, Sanjayan writes, travels not only through a nature preserve but also through a slum where tens of thousands depend on it for water. But without more funding for the government to keep businesses in line with clean water laws, all it’s good for is doing a very, very disgusting bathtime Santa Claus impression.