Halfway into “Citizen Coke,” Bartow J. Elmore describes taking a treacherous journey through an Indian jungle in 2010. He was searching for a Coke bottling plant that had been shut down six years earlier after villagers claimed it had parched their wells and polluted their streams, causing skin and stomach diseases. Thirsty and tired, he stumbled upon a restaurant in a secluded village where the only safe thing to drink was . . . Coca-Cola. “It seemed I had become trapped in the history I had come to investigate,” he writes.