Ganga is considered as the holiest and puriest river in India. Millions of devotees take bath in Ganga everday.

Why Ganga is considered as puriest river?

Well there are two type of belief. One is traditional belief i.e. what people believe and other is scientific belief . We will talk about both traditional and scientific (or ancient) belief with some of its history one by one:

◾Traditional Belief (what people think):

In Hinduism, Ganga is said to cleanse one's sins and bathing in its sacred waters purifies one's inner soul. She is also known as "Tri-path-gamini", which means "the traveler of the three worlds", which are the ether world, earth and netherworld. It is for this very reason that Hindus immerse one's mortal remains in the sacred river for the river grants eternal bliss. Ganges water is also used in all the religious ceremonies.

◾Scientific (Ancient) Belief:

The water of ganga contains enormous amount of Virus called " BACTERIOPHAGE ". This virus kills bacteria and algae, which cause water pollution and thus keep the water pure for long period of time. Bacteriophage is a virus which only infect the bacteria and microbes, doesn't have no side effect on human body.

Ganga have got some special properties, which other rivers do not have. That special property is that it also has self cleansing attributes. Even today, after having being polluted to such an extent, you can keep the Ganges water in bottle for decades and it won't rot. It would remain as fresh as when it was bottled. DS Bhargava, a retired professor of hydrology, who has spent a lifetime performing experiments up and down the Ganges in the plains of India, says that in most rivers, organic material usually exhausts a river's available oxygen and starts putrefying. But in the Ganges, an unknown substance, or "X factor" that Indians refer to as a "disinfectant," acts on organic materials and bacteria and kills them. Bhargava says that the Ganges' self-purifying quality leads to oxygen levels 25 times higher than any other river in the world.

The river irrigates the massive Gangetic doab region, and makes the soil fertile. Directly or indirectly, 200M people are dependent on its sacred waters for their livelihoods.

Bathing in its water at certain locations helps curing several skin related diseases because of high sulphur content.

But that was a few years back. Now on the other hand, an eminent river expert and head of the Ganga Research Laboratory, Institute of Technology (IT-BHU), Prof UK Chowdhary urges to save the Ganga, which he says is gradually losing its oxygen absorption and retention capacity, adding that the Ganga was the only river in the world which had 12ppm of oxygen. "The Ganga was once known as the reservoir of oxygen. But, today, it's oxygen has reduced to 4-8ppm," he said. The Ganges' purifying action has strong scientific evidence, but that power of Ganges is slowly giving up.

In the early times the saints used to attach the names of useful things with the name of god, just to protect them.