The beach around us stretches almost as far as the eye can see. It is a humid, windy afternoon. Every now and then a cluster of visitors arrive: a crimson-clad bearded sadhu (holy man) and a tourist or two.
They wander across the sand to paddle or bathe in the warm, gray waters. Today there are not many visitors; the pickings do not look particularly promising for Dutta.
This place is called Gangasagar. It is the southern tip of a 20-mile-long, finger-shaped strip of land known as Sagar Island, at the western end of the giant delta through which the Ganges passes to sea, via India and Bangladesh.
Hindus consider the island to be a sacred spot. They revere it as the final point of departure for their holy river, Mother Ganga — the place where she merges with the Bay of Bengal after traveling down from the Himalayas and across the plains of north India.
Once a year, millions of pilgrims clamber into ferries for the short journey out to the island to bathe in the waters. That's when Dutta makes his money.
Sagar has only one surfaced road, which runs the length of the island. Yet it is hard to feel sorry for its 150,000 residents: I know deep poverty and deprivation lie behind the thatched mud huts, the palm and banana groves, and the lush paddy fields of rural India. But they do look idyllic, especially here.
So do the island's multitude of lavishly decorated shrines and temples, large and small. We end up staying the night close to one of the larger ones, in an ashram — a religious retreat.
The place turns out to be monastic in every sense. The beds are like large wooden tables with sawn-off legs. Mosquitoes lurk in the dank shadows, and mount an all-night offensive.
We eat an evening meal of rice, vegetables and dal (lentils) in a stark communal hall. A grim-faced young man ladles food from what resembles a farmyard bucket.
As you'll hear in Part 5 — the last report of our series— Dutta, the photographer, is not the only one working the beach at Gangasagar.
As we talk, we can see a small wiry woman in the distance, silhouetted against the hazy horizon. Bent double, she is raking the sand with a small fork, making wide arcs as she systematically works back and forth.
Her name is Asura Bibi. She belongs to the old India: the hungry India in which eight out of 10 infants are anemic (a figure that has worsened during the boom years), the India where getting sick means going broke.
With Asura's story, as you'll hear, we end our odyssey through India, and say farewell to the most remarkable of rivers, Mother Ganga.