ALLAHABAD, India (AP) — Led by heads of monasteries arriving on chariots and ash-smeared naked ascetics, millions of devout Hindus plunged into the frigid waters of the holy Ganges River in India on Sunday in a ritual that they believe will wash away their sins.

Sunday was the third of six auspicious bathing days during the Kumbh Mela, or Pitcher Festival, which lasts 55 days and is one of the world’s largest religious gatherings.

By the end of the day, as many as 30 million devotees were expected to have taken a dip at the Sangam, the confluence of three rivers — the Ganges, the Yamuna and the mythical Saraswati, at the edge of Allahabad in northern India.

The auspicious bathing days are decided by the alignment of stars, and devout Hindus believe a dip in the sacred river on one of these days will wash away their sins and free them from the cycle of death and rebirth.

The first to bathe Sunday were the heads of different Hindu monasteries who reached the bathing areas, called ghats, accompanied by marching bands. Some arrived on silver chariots and others were carried on palanquins by their followers.

They were followed by the Naga sadhus — ascetics with ash rubbed all over their bodies, wearing only marigold garlands.

Over the years, modernity has begun to mingle with the centuries-old tradition of the Kumbh Mela, with many of the ascetics and religious heads flaunting expensive laptop computers and photography equipment.

Hundreds of sadhus wandered along the bathing areas carrying small video cameras and smartphones.

"We are using this modern technology to keep ourselves updated. This will also help us in propagating our religion better," said Maharaj Nirupanand, an ascetic in his early 40s. "Not everyone can come to Kumbh. We can send these pictures to them so that they can feel the enormity of this occasion."

According to Hindu mythology, the Kumbh Mela celebrates the victory of gods over demons in a furious battle over nectar that would give them immortality. As one of the gods fled with a pitcher of the nectar across the skies, it spilled on four Indian towns — Allahabad, Nasik, Ujjain and Haridwar.

The Kumbh Mela is held four times every 12 years in those towns. Hindus believe that sins accumulated in past and current lives require them to continue the cycle of death and rebirth until they are cleansed. If they bathe at the Ganges on the most auspicious day of the festival, believers say they can rid themselves of their sins.