Month after month, snow blankets the great wall of rock that separates India from China and Tibet. It settles, compacts, changes its crystalline structure, freezes solid. The mountain peaks, the highest on earth, are covered with endless fields of ice. Sometimes people call them the Third Pole.
No one really knows how many glaciers there are in the Himalayas. Some say ten thousand; some say more. In India, the second largest is the Gangotri Glacier. In our warming world, it isn't as big as it used to be. Before I left New Delhi for the mountains, I went to see India's best-known glaciologist, Syed Iqbal Hasnain. A jovial, white-haired, grandfatherly man, he told me that the glacier used to cover more than two hundred and fifty square kilometers—about a hundred square miles. "But now it's breaking up in many places. You will see blocks of dead ice that are no longer connected to the main ice body." He chuckled, which seemed odd for someone who was so alarmed by his own findings. But I've often found that maintaining a sense of humor is a common trait among scientists engaged in possibly hopeless endeavors.
The tip of the Gangotri Glacier—what scientists call its toe, or its snout—has receded by about two miles since the first European explorers reached it two hundred years ago. It loses another sixty feet every year. When glaciers decay, they become sad, derelict things. The ice cracks and crumbles and turns a dirty pale blue before melting away altogether. At the snout of the Gangotri Glacier, a thin stream of gray, silt-laden water trickles from a cave surrounded by a bleak, colorless rubble field. So much of the ice is gone that you would have to use your poetic imagination, or look at a very old photograph that shows the long-vanished arch of the cave, to understand why, for centuries, Indians have called it Gaumukh: the Cow's Mouth.
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Two hundred miles downstream, the stream reaches a town called Devprayag, which sits on a triangular promontory. By now it has picked up countless tributaries, passed through innumerable villages and pilgrimage towns and a couple of dams, and become a broad, whitecapped torrent. At Devprayag, it is joined by another river of roughly equal size, the Alaknanda, which flows deep and green from the east. From there to the Indian Ocean, another thirteen hundred miles, it is Ma Ganga—Mother Ganga, or, as the British chose to call it, the Ganges.
At Haridwar, the "Gateway of God" and one of the holiest places in Hinduism, the Ganges leaves the mountains and enters the endless dusty plains of North India. Its main tributary, the Yamuna, runs dead and black through Delhi, then skirts the walls of the Taj Mahal in Agra before eventually joining the Ganges in a place that is sacred to Hindus but carries the name it was given by an invading Muslim emperor: Allahabad, City of God. Farther on, bodies burn around the clock in another city, one that has four names: Kashi, Benares, Banaras, Varanasi. The hinterland towns and villages of the great Gangetic Plain seem sometimes to encapsulate everything that ails India: caste prejudice, corruption, rape and sex trafficking, Hindu-Muslim violence, poverty, and pollution. A pall of brown dust and soot hangs over the fields for most of the year, rising from the cookstoves that burn firewood, kerosene, and cow dung in tens of thousands of villages. Three kilometers thick, the brown cloud drifts northward to the Himalayas, turning the ice dark, increasing the speed at which it is melting. But the northern plains, especially the state of Uttar Pradesh with its two hundred million people, also control India's political destiny.
When the river finally approaches its delta—the Hundred Mouths of the Ganges—geographers and believers part company. The Ganges divides. Names change. Swollen by the power of the Brahmaputra, the Son of Brahma, the main stem sweeps eastward into what used to be East Bengal and is now Bangladesh. From the geographer's point of view, this is the true Ganges. It picks up the Jamuna, becomes the Padma, morphs finally into the Meghna, whose estuary is twenty miles wide. But the sacred Ganges of Hinduism—which is also to say the secular Ganges of the British East India Company and the Raj—peels off before the border and heads south, changing its name again as it cuts through the fertile rice fields and palm groves of West Bengal. By the time it reaches Calcutta, present-day Kolkata, it has become the Hooghly.
Seventy miles south of the megacity, and one thousand, five hundred and sixty-nine from the Gangotri Glacier, the Hooghly arrives at last at a flat, oval island, the final point of land. At its southernmost tip is Gangasagar, the last of the river's innumerable pilgrimage sites, where the river dumps a coffee-colored plume of silt a mile long into the Indian Ocean.
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