An Indian Hindu family walks on the shallow banks of the Yamuna river, covered with chemical foam caused by industrial and domestic pollution, during Chhath Puja festival in New Delhi on Nov. 2, 2019. Despite the river being accorded the status of a living human entity by an Indian court, untreated sewage and industrial pollutants have turned it into one of the most polluted rivers in the world. The Yamuna is one of the major tributaries of the Ganges. (AP Photo/Altaf Qadri)
More than 2,000 years ago, a powerful king built a fort on the banks of India's holiest river, on the fringes of what is now a vast industrial city.
Today, little of the ancient construction remains, except for mounds of rubble that tannery workers pick through for bricks to build shanties atop what was once the fortress of the great King Yayati.
And Kanpur, where Yayati built his fort, is a city known for its leather tanneries and the relentless pollution they pump into the Ganges River.
For more than 1,700 miles, from the Gangotri Glacier in the Himalayas to the Bay of Bengal, the Ganges flows across the plains like a timeline of India's past, nourishing an extraordinary wealth of life. It has seen empires rise and fall. It has seen too many wars, countless kings, British colonials, independence and the rise of Hindu nationalism as a political movement.
In India, the Ganges is far more than just a river. It is religion, industry, farming and politics. It is a source of water for millions of people, and an immense septic system that endures millions of gallons of raw sewage.
To Hindus, the Ganges is "Ganga Ma" — Mother Ganges — and a center of spiritual life for more than a billion people. Every year, millions of Hindus make pilgrimages to the temples and shrines along its shores. To drink from it is auspicious. For many Hindus, life is incomplete without bathing in it at least once in their lifetime, to wash away theirs sins.
A Hindu pilgrim takes a holy dip on Makar Sankranti festival on Sagar Island, an island in the Ganges delta, in the eastern Indian state of West Bengal Jan. 15. (AP Photo/Altaf Qadri)
Mouni Baba, a Hindu holy man, fetches water from a stream at the feet of Mount Shivling in Tapovan, in the northern Indian state of Uttarakhand, May 10, 2019. (AP Photo/Altaf Qadri)
The Milky Way glows above the 6,856-meter-tall Bhagirathi peaks as seen from Tapovan, May 10, 2019. Bhagirathi peaks feed the Gangotri Glacier. (AP Photo/Altaf Qadri)
A Hindu holy man meditates near Gaumukh, a snout of the Gangotri Glacier at an altitude of 4,000 meters in the northern Indian state of Uttarakhand, May 11, 2019. (AP Photo/Altaf Qadri)
Schoolgirls walk along a road overlooking Tehri Dam on the Bhagirathi river in the state of Uttarakhand, May 13, 2019. The Bhagirathi is one of the two sources that form the River Ganges. (AP Photo/Altaf Qadri)
The confluence of Alaknanda and Bhagirathi rivers, the start of the River Ganges, is illuminated at twilight in the town of Devprayag, Uttarakhand state, May 13, 2019. (AP Photo/Altaf Qadri)
A cremation worker sits by the body of an elderly man, wrapped and weighed down by a large rock, before throwing the body into the river Ganges as per his final wish, in Varanasi, India, Oct. 18, 2019. (AP Photo/Altaf Qadri)
Funeral pyres burn at Manikarnika Ghat, one of the oldest and most sacred place for Hindus to be cremated, on the banks of river Ganges in Varanasi, India, Oct. 18, 2019. (AP Photo/Altaf Qadri)
A man carries a bucket of water while people wash utensils, brush their teeth and bathe in the polluted waters of the river Hooghly, a distributary of the river Ganges in Kolkata, West Bengal, Oct. 11, 2019. (AP Photo/Altaf Qadri)
Chemical foam caused by industrial and domestic pollution is seen flowing toward a figurine stuck in the shallow waters of Yamuna river in New Delhi, Oct. 8, 2019. (AP Photo/Altaf Qadri)
But all is not well with the Ganges.
Pollution has left large sections of it dangerous to drink. Criminal gangs illegally mine sand from its banks to feed India's relentless appetite for concrete. Hydroelectric dams along the river's tributaries, needed to power India's growing economy, have infuriated some Hindus, who say the sanctity of the river has been compromised.
And over the past 40-some years, the Gangotri Glacier — source of almost half the Ganges' water — has been receding at an increasingly frightening pace, now losing about 22 meters per year.
For millennia, the Gangotri's glacial melt has ensured the arid plains get enough water, even during the driest months. The rest comes from Himalayan tributaries that flow from the colossal chain of mountains.
As the Ganges flows across the plains, its once clean and mineral-rich water begins collecting the toxic waste from the millions of people who depend on it, becoming one of the most polluted rivers in the world. Millions of liters of sewage, along with heavy metals, agricultural pesticides, human bodies and animal carcasses, are dumped into the Ganges every day.
At times, officials try to fix things, but vast stretches of it remain dangerously unhealthy.
Still, to Hindus, the river remains religiously pure.
Hindu women walk on silt, deposited by monsoon floods, along the banks of the river Ganges to perform daily morning rituals in Varanasi, in Uttar Pradesh state, Oct. 18, 2019. (AP Photo/Altaf Qadri)
A crowd gathers for a prayer ceremony dedicated to the river Ganges in Varanasi, India, Thursday, Oct. 17, 2019. (AP Photo/Altaf Qadri)
Women wash their household items by a drainage flowing into the river Ganges in Varanasi, Uttar Pradesh, Oct. 18, 2019. (AP Photo/Altaf Qadri)
Smoke rises from chimneys of leather tanneries in Kanpur, an industrial city on the banks of the river Ganges, India, June 23. (AP Photo/Altaf Qadri)
Devotees take ritualistic dips alongside elephants at the confluence of river Ganges and river Gandak to mark the beginning of the centuries-old Sonpur mela, the largest cattle fair in Asia, in Bihar state, Nov. 12, 2019. (AP Photo/Altaf Qadri)
Hindu pilgrims walk on a bridge before dawn at Sangam, the confluence of rivers Ganges, Yamuna, and mythical Saraswati during the Magh Mela festival in Prayagraj, Uttar Pradesh state, Jan. 30. (AP Photo/Altaf Qadri)
A dog walks on a beach that was once a village on Sagar Island, one of the islands that make up the Sundarbans, a low-lying delta region of about 200 islands in the Bay of Bengal, India, Jan. 14. (AP Photo/Altaf Qadri)
An Indian worker drinks water as processed rawhide are laid to dry at a tannery in Kanpur, an industrial city on the banks of the river Ganges, June 24. (AP Photo/Altaf Qadri)
Hindu pilgrims huddle together after being forced by high tide to flee from their camps on the eve of Makar Sankranti festival on Sagar Island in the Ganges delta, in West Bengal, Jan. 14. (AP Photo/Altaf Qadri)
An Indian fisherman wades through shallow waters to reach the banks of the river Ganges after sundown in Bhagalpur in the eastern Indian state of Bihar, Nov. 13. (AP Photo/Altaf Qadri)
Every year, tens of thousands of Hindus bring the bodies of their loved ones to be cremated at the Ganges, in the city of Varanasi. A Hindu who dies in the city, or is cremated alongside it, is also freed from that cycle of birth and death.
After Varanasi, the Ganges continues its eastward journey through endless farmland as it nears the coast, eventually splitting off into ever-smaller rivers in the great wilderness of her delta. The biggest river, the Hooghly, heads south toward the sea, passing through Kolkata, the largest city in eastern India. Once the capital of the British raj, known as Calcutta, today the metropolis is home to nearly 15 million people.
Eventually, its waters spill into the Bay of Bengal.
Up near the Gangotri Glacier, a genial Hindu holy man who goes by the name Mouni Baba and spends much of his life in silent meditation sees all of mankind reflected in the river.
"Human existence is like this ice," he said. "It melts and becomes water and then merges into a stream. The stream goes into a tributary which flows into a river and then it all ends up in an ocean. Some [rivers] remain pure while others collect dirt along the way. Some [people] help mankind and some become the cause of its devastation."