The river above is the Sumida River that flows 17 miles through Tokyo, Japan. It discharges into the Tokyo Bay and the Pacific Ocean. I took these photos during a vacation to Japan this summer. The cruise boat shown in picture 1 brings me from Asakusa to the Bay.
I thought that the boat would encounter torrent when close to Tokyo Bay. Out of my expectation, the water is placid and smooth throughout the entire journey. Comparing to highly polluted Ganges River, I was amazed by the peaceful interactions between densely populated central Tokyo and Sumida river. However, the river was actually deteriorated and contaminated until recently. In the 1950s and 1960s, due to rapid urban development, the river no longer became a habitat for aquatic and was called a “River of Death”. Its biochemical oxygen demand reached 60 milligrams per liter in the late 1960s, meaning the pollutant were so many that aerobic organisms do not have enough oxygen to oxidize and break down them.
To make the river as clean as shown in the pictures, the government banned factories pouring effluent into the water, collected human waste, and built some new sewer systems.
