Millions of Hindus are expected to gather in the northern Indian city of Allahabad for a dip in the Ganges River Friday, considered the most auspicious day in the "Ardh Kumbh Mela" religious festival.

Authorities say they expect more than 20 million to bathe in the chilly waters by the end of the day, which marks the half-way point in the six-week-long festival.

The day is celebrated as the "Mauni Amavasya" or the new moon, starting a new lunar month, which the faithful observe with silent prayers.

The "Ardh Kumbh Mela" festival is held every six years. It commemorates a legendary battle Hindus say took place between gods and demons when the universe was created, fighting over a pitcher of the nectar of immortality.

The festival was marred last week when Hindu holy men threatened a boycott of the ceremonies, saying the Ganges was too polluted.

The issue was resolved when state officials said they would release fresh water from canals and dams to help improve water quality.

Some information for this report was provided by AFP