Photo gallery: Maha Kumbh Mela in India subject of Harvard study

NEW DELHI - What do you think could happen if the entire populations of Shanghai and New York were to spend 55 days on a sandy river bank, living frugally out of tents, with no supermarkets and using dirty public toilets?

Chaos? Epidemic? Mob violence? Think again.

Millions of Hindu pilgrims are descending on a northern Indian city to participate in the ancient riverside religious fair, Maha Kumbh Mela, or the Great Pitcher Festival, the first wave of about 100 million expected to attend what is billed as humanity’s largest congregation over 55 days that began on Jan 14.