Over the bridge they came, Hindu holy men by the tens of thousands, the most devout naked and dusted with sacramental powder, marching toward the bathing pool in the Ganges where the water is considered holiest on this most propitious of days. Shouting and singing, waving tridents or spears, the naked mystics, or naga sadhus, were granted the first plunge. Then came the gurus and swamis, wrapped in saffron robes, a few shaded by beaded parasols. One swami was delivered into the water on the shoulders of his disciples. For 20 minutes, they frolicked, as other pilgrims watched from nearby rooftops. And then time was up. The police tweeted their whistles and began nudging the group out of the sacred water. There were still untold thousands of holy men waiting to take a dip. Wednesday was the culmination of the Hindu religious festival known as the Kumbh Mela, a staggering outpouring of humanity that also represents a staggering logistical challenge. Since January, tens of millions of pilgrims have arrived in this city by train, plane, bus or foot for the privilege of bathing in the Ganges on certain auspicious dates. On Wednesday alone, 10 million people were estimated to have entered the water. The crowds are so massive that safety is a serious concern. Not least is the challenge of managing the rival sects of holy men, the self-described defenders of the Hindu religion for whom the Kumbh Mela is both a sacred ritual and a demonstration of their status. In years past, they have bickered with each other, or with the government, arguing over issues like which group should be allowed to bathe first or whether their photographs could be taken during the holy dip. 'They are very egoistic,' said Anand Bardhan, the administrator overseeing the Kumbh. 'One moment they suddenly become angry and the next moment they will shower lots of affection. You need to understand their nature.' This year, the police assigned a special officer as a liaison to the various sects who helped negotiate a consensus on the bathing schedule. The first in the water this year were followers of the order known as the Niranjani. But tragedy struck Wednesday morning. The police say the Juna sect was beginning its procession toward the Ganges when one of their vehicles hit several people in the crowds. People panicked and stampeded. Seven people were killed, though it is unclear if they died from the accident or the stampede. Leaders of the Juna canceled their procession, instead choosing to bathe at a different spot on the Ganges, and blamed the authorities for failing to adequately clear their route to the river. Mahant Hari Giri, general secretary of the Juna, said that leaders decided it would be inappropriate to resume their march through the city but that the group had not boycotted the ritual, as some had reported. 'It was not possible to take the whole procession,' he said. 'But we have not boycotted the holy bath. We did take a dip in the Ganges.' The Kumbh Mela derives from Hindu mythology, which holds that gods and demons struggled over a pitcher, or kumbh, containing the drink of immortality. As the gods raced toward heaven, drops of the sacred nectar spilled out onto four locations on the river: Allahabad, Ujjaink, Nashik and Haridwar. Today, the Kumbh Mela is held every three years, rotating among the four cities, meaning that each hosts every 12 years. Tucked in the foothills of the Himalayas, Haridwar is a challenging place to host tens of millions of people. The Kumbh Mela is conducted in the middle of the city, and many pilgrims insist on taking their dip in the holiest spot, known as Har Ki Pauri, which is roughly the size of three Olympic swimming pools. Authorities estimated that roughly 100,000 people an hour entered the water at Har Ki Pauri on Tuesday and Wednesday. Many pilgrims believe that a dip in this spot on the appointed day will allow them to break the cycle of reincarnation. 'This is Mother Ganga!' said Ramesh Varma, 23, dripping wet in his underwear after a dip. He traveled 10 hours by bus and then walked five hours to reach Har Ki Pauri. 'The idea is that whatever sins you have are washed away. This is a new beginning of your life. This is what I feel.' Based on the position of the sun, the moon and Jupiter, Wednesday was judged the most auspicious day for the bath. For days, pilgrims had poured into Har Ki Pauri until Wednesday morning, when the police cordoned it off to prepare for the arrival of the holy men. Prahbu Nath Ohja, the officer appointed as liaison to the various sects, said authorities had hoped to avoid the problems that occurred in 1998 when the Kumbh Mela was last held in Haridwar: an angry scuffle broke out between the Juna and the Niranjani schools not long before the dip. To protest, both groups boycotted the bathing. This year, Ohja organized meetings with the 13 different religious schools, or akharas, mediated talks between the Juna and Niranjani and got leaders from all groups to agree on a strict bathing schedule at Har Ki Pauri. 'That was our challenge,' Ohja said. 'We tried to explain to them that because of this, the image of the akharas had suffered inside and outside India.' For the ordinary pilgrims, many of them achingly poor and carried along by faith and little more, the Kumbh is a journey of personal faith, if also an epic road trip. For weeks, thick crowds have poured out of the Haridwar railway station, overwhelming the city. Every hotel room is taken, and most pilgrims find space on the ground, beneath the shade of a tree or at one of the squatters' camps erected by the government. Ram Devi Sahu arrived Monday with a group of 25 women and girls, ranging in age from 11 to 85, everyone having traveled overnight by train. They went directly to the Ganges for a preliminary dip and toured different ashrams, collecting blessings from holy men, until nightfall arrived, and the group splintered in search of places to sleep. Sahu and eight others found a wide ledge beside a city street. It seemed inviting. 'We saw this empty platform, so we put our luggage here,' said Sahu, 58. 'It was nice. We can eat in the market.' Sahu seemed quite delighted. Her budget for the week was about $40. 'We go to different temples every night,' she said. 