"Is the Ganga Really Unusual?"

Here what scientist William R. Corliss (55 books and a consultant to
several corporations including Time-Life Books and General Electric)
wrote in 2000:
* Ganges water does not putrefy, even after long
periods of storage. River water begins to putrefy when lack of oxygen
promotes the growth of anaerobic bacteria, which produce the telltale
smell of stale water.
* British physician, C.E. Nelson observed that
Ganges water taken from the Hooghly -- one of its dirtiest mouths -- by
ships returning to England remained fresh throughout the voyage.
*
In 1996 the British physician E. Hanbury Hankin reported in the French
journal 'Annals de l'Institut Pasteur' that cholera microbes died
within three hours in Ganges water but continued to thrive in distilled
water even after 48 hours.
* A French scientist, Monsieur Herelle,
was amazed to find "that only a few feet below the bodies of persons
floating in the Ganges who had died of dysentery and cholera, where one
would expect millions of germs, there were no germs at all.
* Quantitatively, the Ganges seems to clean up suspended wastes fifteen to twenty time faster than other rivers.