Maha Kumbh is celebrated at Haridwar once in every 12 years. The great bathing festival of the Kumbh Mela at Haridwar is in now in this year - 2010.
Some Hindus also believe life is incomplete without taking a bath in Ganges at least once in their lives. Many Hindu families keep a vial of water from the Ganges in their house.
Ceremonial bathing in the sacred Ganga as she descends from her celestial home to journey through the Himalayas to the plains of India, is a sacred ritual from time immemorial. The Kumbh Snan Parva is much more significant than a ritualistic dip in the holy river. It is a tribute to the Hindu way of life, an affirmation of faith and a renewal of our deep-seated beliefs. The holy bath at a Kumbha is said to be equal in merit to thousands of snans during the month of Kartik, hundreds of Magh snans and crore snan in the river Narmada during Vaishakh. It's fruit is said to be equivalent to thousands of Ashwamegh Yajna *, hundreds of Vajpaye Yajna, and lakhs of parikrama around the world.
* The Ashvamedha was one of the most important royal rituals of Vedic religion, described in detail in the Yajurveda (TS 7.1-5, VSM 22–25[1] and the pertaining commentary in the Shatapatha Brahmana ŚBM 13.1–5). The Rigveda does have descriptions of horse sacrifice, notably in hymns RV 1.162-163 (which are themselves known as aśvamedha), but does not allude to the full ritual according to the Yajurveda.
At Haridwar, there are many bathing ghats, the chief one being at Har Ki Pauri. It is said to have been constructed by King Vikramaditya in memory of his brother, Bhartrihari, who is believed to have come to Haridwar to meditate on the banks of the sacred Ganga. While some historians date Vikramaditya�s reign as first century BC others suggest it was in the sixth century AD. This bathing ghat is also known as Brahmakund Ghat. The other well-known ghats in Haridwar are Ram Ghat, Vishnu Ghat, Asthi Parwah Ghat , where the ashes of the deceased are immersed, Subhash Ghat named after Netaji Subhash Chandra Bose, and Gau Ghat where the sin of gau-hatta or cow slaughter is atoned for.
The Kumbh is mythologically related to the churning of the oceans to extract amrit or the nectar of immortality. The devatas or gods and the asuras or demons, together churned the oceans. The pot of ambrosia was handed to Brihaspati, (Jupiter) Surya,(Sun) Chandra (Moon) and Shani (Saturn). In the process of the ensuing tussle to get it, which lasted 12 god-days, equal to 12 human years, a few drops spilled from the kumbh or pitcher in which the Amrita was being carried. This nectar fell at Allahabad, Haridwar, Nasik and Ujjain, sanctifying these places.
The Kumbha Mela is held at these four sacred places - on the banks of the holy Ganga at Haridwar where it descends from the mighty Himalayas to the plains of India, at the confluence of the Ganga, Yamuna and the mythical Saraswati called the Triveni Sangam at Prayag or Allahabad, beside the river Kshipra at Ujjain and on the banks of the Godavari at Nasik.
At each of the four places the Kumbh festival is celebrated once every twelve years, coinciding with one round of Jupiter through the zodiac. Since the three cosmic powers played their role, the Kumbha is celebrated when Jupiter, the Sun and Moon are in particular astrological positions in the almanac.
When Jupiter is in in the sign of Aquarius, when the sun is in Aries and Moon is in Sagittarius, the Auspicious Kumbh at Haridwar occurs. When Jupiter is in Taurus and the Sun and Moon in Capricorn, it is celebrated at Prayag or Allahabad. At Nasik it is held when Jupiter is in Leo and the Sun and Moon are in Cancer. At Ujjain the Kumbh Mela occurs when Jupiter is in Leo and the Sun and Moon in Aries.