River Ganga is officially declared the National River of India. The Ganges or Ganga, is a trans-boundary river of India and Bangladesh. The 2,525 km (1,569 mi) river rises in the western Himalayas in the Indian state of Uttarakhand, and flows south and east through the Gangetic Plain of North India into Bangladesh, where it empties into the Bay of Bengal. By discharge it ranks among the world’s top 20 rivers. The Ganges basin is the most heavily populated river basin in the world, with over 400 million people and a population density of about 1,000 inhabitants per square mile (390 /km2).
The Ganges is the most sacred river to Hindus and is also a lifeline to millions of Indians who live along its course and depend on it for their daily needs. It is worshiped as the goddess Ganga in Hinduism. It has also been important historically: many former provincial or imperial capitals (such as Patliputra, Kannauj, Kara, Kashi, Allahabad, Murshidabad, Munger, Baharampur and Kolkata) have been located on its banks.
Kumbh Mela is a mass Hindu pilgrimage in which Hindus gather at the Ganges river. The normal Kumbh Mela is celebrated every 3 years, the Ardh (half) Kumbh Mela is celebrated every six years at Haridwar and Prayag, the Purna (complete) Kumbh takes place every twelve years, at four places (Prayag (Allahabad), Haridwar, Ujjain, and Nashik). The Maha (great) Kumbh Mela which comes after 12 ‘Purna Kumbh Melas’, or 144 years, is held at Allahabad.