Mystics' river: Pilgrims take the plunge in the Ganges

You could see the lights from hundreds of miles away - they had turned the night sky over this usually sleepy, dirt-poor corner of India a bright orange. And as we came over a rise, we saw them spread out, thousands of lights glittering along the river banks. There were spinning wheels of lights that whirled round and round, lights that burst in imitation of a firework going off, lights that cascaded down what looked like Hindu temple towers, sprung up suddenly on the soft sand river banks. This was the Las Vegas of holy men. Crowning one of the ornate gateways on the sand was a large illuminated portrait of a sadhu. Next to him was a picture of a follower, complete with a motorised arm that gently fanned his master.

This was the scene that greeted millions of Hindu pilgrims as they massed at the city of Allahabad yesterday for the sacred ritual of bathing in the river Ganges. And as dawn approached, sadhus, or holy men, emerged from tents lining the shore, naked in front of the crowds, and processed to the river bank to immerse themselves in the water.

Others were preparing ornate silver thrones that would carry them to the water's edge - perched on the back of a trailer driven by a tractor.

It can be surprisingly cold in north India in January, and by this stage the temperature was around 3C. A fine mist was hanging over the river banks. The naked holy men stood unabashed in front of the gathered crowds, and seemingly oblivious to the cold.

They were heading for what is known here as a "holy dip", a brief immersion in the water at the confluence of the Ganges and the Yamuna that is believed to wash away all of a pilgrim's sins. The water did not look inviting - in fact it looked distinctly chilly. "When you go in you do not feel cold at all," said Nigamber Yogendra Puri, one of the sadhus. "You feel warm because it is God's will."

Looking somewhat incongruous beside the naked sadhus was Ashok Kumar Singh. He had finished his "holy dip" and dressed again in smart shirt and trousers, but had left his black slip-on shoes to one side and was standing on the sand in his socks to pray as the sun rose. A civil servant, Mr Singh had taken special leave to be here. He could only stay one day and would have to return to work the next day.

But Mr Singh was a rare figure among the crowds. Most were from a poorer background - there were few CEOs or call centre workers to be seen. On a hilltop a group of young men were dancing excitedly Bollywood-style, as one of them beat a large drum. They were a party of milkmen from Madhya Pradesh, in central India, and it was their first time for a "holy dip". They had clubbed together to travel here.

Some of the pilgrims were decidedly exotic. We stopped one man to ask where he had come from. He smiled enigmatically and pointed at the sky. "You mean from the sky?" we asked. He nodded beatifically and smiled. A sign above a tent near by read: "All India Saints' Association".

Bajrav Giri, a sadhu clad in orange robes, with long hair and matted beard, had come from Jaipur in Rajasthan, a trip of several hundred miles, but he had not had to pay a penny. He had begged lifts from cars and trucks along the way, relying on the respect Indians still have for sadhus, who renounce all worldly goods and relationships to live a life of pure prayer. Even the buses had let him ride for free. This is an India apart from the call centres and flashy new cars of the cities - an India that has barely changed in centuries.

What looked like carved marble Hindu temples turned out on closer inspection to be life-size models made out of plywood frames and white sheeting. Around them a tent city had been built along the river banks to house the pilgrims. It could have been a refugee camp, but for the fact that everyone was happy.

Hindus believe that, during a battle between gods and demons over a pitcher of divine nectar, four drops fell to earth. Bathing festivals are held every six years at the sites. For the poor who make up the mass of pilgrims, they are a major event. Many had come to stay for several weeks.

The crowds were far smaller than expected yesterday, the first of several auspicious bathing days - and the reason may have been something else that was making the water look uninviting: the gleam of toxic sludge on the surface.

The Ganges and Yamuna have been getting steadily more polluted over the years, both by factories pumping chemical waste into them, and by the influx of untreated sewage. The Yamuna, which passes through the capital, Delhi, before it reaches Allahabad, is particularly noxious, full of foul-smelling black slime.

This year, the holy men have finally had enough, and a major sadhus' organisation has announced it will boycott the "holy dip" this year to force the national government to clean up the rivers. Thousands of sadhus have even threatened to commit mass suicide unless action is taken, and the government also does something about falling water levels.

The boycott did appear to be having an effect yesterday, with overzealous police, who had been expecting much bigger crowds, herding the pilgrims unnecessarily.

In an effort to calm the sadhus' anger, the authorities have flushed the rivers with fresh water from canals and dams upstream. They have also kept dams open to try to raise the dwindling water level - to the dismay of farmers who say that water they desperately need for irrigation is disappearing to replenish the Ganges.