It’s late evening in the city of Prayagraj and the roadside vendors selling snacks are packing up their wares to shut for the night.

Scores of naked Hindu ascetics smeared in holy ash charged into the water of holy rivers in northern India on Tuesday, dreadlocks flying, during the first 'royal bath' of the Maha Kumbh Mela, or Great Pitcher Festival.

For pilgrims at the largest gathering of humanity, ritual bathing in India's holy rivers includes a key challenge -- finding your family and clothes after the chilly dip.