India, Feb. 1 -- The Kumbh Mela attracts millions of devotees to the Prayagraj Sangam, where the Ganga, Yamuna and the mythical Saraswati meet. The vast sandy stretch at the Sangam is transformed into a sprawling temporary megacity for the duration of the Mela. This time, tragedy struck when at least 30 persons were killed in a pre-dawn stampede on the holy day of Mauni Amavasya. But such accidents are an exception, which is why the management of the Kumbh is spoken about as a masterly exercise in crowd management....