India, April 19 -- It's one thing to fall down a rabbit hole. Another thing entirely when that rabbit hole is a sewer. But then the story of 21st-century sanitation is shaping up to be an explosive blockbuster. Hold on to the term blockbuster. It will make sense in a bit. First, the villain origin story. In 2013, sanitation workers in Kingston upon Thames, London began to stumble upon gigantic, rock-hard clumps blocking the city's drains. One, the size of a bus, weighed 15 tonnes. No one put it there. It formed bit by bit when wet wipes and diapers (both advertised as the flushable kind) congealed with the fat, oil and grease that goes down sewers too, to create a fatberg. By 2017, a 130-tonne monster had been found in the sewers of Whitech...