Your new book, Ganga: A Journey Down the Ganges River, examines the whole of India's Ganges River. How does visiting the Ganges figure into visiting India and understanding the country?

Ganga is the essence, the heart of India. It doesn't matter that it's in the north, that most Indians will never actually visit any stretch of the river in their lifetime. For most Indians Ganga is the symbol of Bharat, of India. It's what defines India. Indeed, there is a saying that all rivers in India are Ganga, which is why it makes perfect sense for most people to be cremated in their local river, because in their minds it is linked to the great goddess in her liquid form. This duality of Ganga - as metaphysical goddess (of the mind) and liquid reality (the river) and the ease with which all Indians can happily co-exist in these two worlds, is also basic to any understanding of what makes Indians tick. So understand a little about Ganga and you will have opened doors to understanding India on her own terms. You simply can't figure her out if you judge her solely on Western terms. To understand India one has to think outside the box.

You say that "Ganga is in danger of dying." Why is that and what makes you optimistic or pessimistic about the future of the Ganges? How aware or concerned do you think India is about the river's future?

Ganga is in danger of drying up in places and at certain times of the year when overuse becomes chronic. She simply can't replenish herself outside of the monsoon season. Unfortunately, this imbalance between supply and demand is most acute in the northwest, precisely the area that is most frequented by Western visitors. In the East, which has few or no hotels and roads, the river is full of water and quite destructive of land, animals and humans.

Indians are basically unaware that certain reaches are periodically drying up. Few outside of those living along her banks, really comprehend that Indians are consuming too much water. But can you really blame them? How many Americans, for example, really understand that something similar and as momentous is happening across the United States, that aquifers are being depleted beyond the tipping point?

Most ordinary Indians have heard about pollution of Ganga. If they've been to the river they've seen with their own eyes. Yes, they are concerned, but too often not enough to actually support efforts to prevent households and industries from using the river as a rubbish dump for wastes, often toxic. After all, since Ganga is a goddess and can purify human souls, presumably she can also cleanse mere superficial dirt? So why get too bothered?

Maybe if they see the dried-up river bed in places like Allahabad it will dawn on them that they have to do something about restoring the amount of water in the river too? Some will comfort themselves that Ganga the goddess lives in their mind, so can never dry up and die. But a dried-up river bed may shake them up and start to question their faith!

The city of Varanasi is a major pilgrimage site on the Ganges. Beyond the ghats of Varanasi, where would you recommend people go and what should they see to best appreciate the Ganges?

If you get the chance and the weather is right, go to Gaumukh and Gangotri - the source of Ganga. But you need to go with an experienced guide. I suggest Nidhish Sharma at Garhwal Adventure. Still in the Himalayas, no understanding of the river and its hold on the Indian imagination, is complete without a brief visit to Devaprayag, where two mountain rivers - the Bhagirathi and Alaknanda - meet to officially become Ganga. A couple of hours south is Rishikesh, which has no real religious significance but is a magnificent site, then Haridwar, one of the great pilgrimage sites of India. You should attend the evening aarti at Har-ki-pairi ghat. In all these places don't expect five-star hotels. This is noisy, chaotic, lively India.

I hesitate to suggest Kanpur because it has no religious significance but is the example everyone quotes as an example of pollution. Again, no great hotels or riverside access.

But the place one should go is Allahabad, where Ganga and Yamuna merge at the Sangam. It's basically a giant sandbank formed where the two currents meet. Bathing here will cleanse you of sin. Throwing the ashes of a cremated body here ensures that the soul of the departed person will be carried by Ganga into the next world. How? When Ganga flows back into the sea in the Bay of Bengal it's essentially flowing back down into the netherworld. For many Hindus, bathing at the Sangam, rather than at Varanasi, is perhaps the most auspicious place they can select.

When the visitor eventually reaches Varanasi he or she needs to let the strangeness of it all wash over them. I think what I wrote in my book (pp 119-121) says it still better and more succinctly than any interview:

"A trip one early morning on a country boat with Anil and Rinku, our boatmen, shows why Varanasi makes such a huge impression. Start from the ghat I am most familiar with—Asi Ghat. People are performing their religious ablutions, others are simply scrubbing down with soap and shampoo. For at least the last three hundred years visitors have found scenes of mourning, bathing along the river Ganga visually and emotionally arresting. It's the sheer size of the ghats at Varanasi - a gentle arc of three miles on tall bluffs.

Along the ridge are a bewildering confusion of massive and picturesque masonry "stone platforms, soaring stairways, sculptured temples, majestic palace, softening away into the distances." And everywhere human life in noisy motion.

Long flights of stone ghats lead down to the river, crammed with thousands upon thousands of Hindus going about their morning prayers waist deep in the river. Hands cupped, eyes closed, they pray to Ganga, Surya, to Shiva, Vishnu and many more besides, letting the water of Ganga dribble through the palms of their hands. The bather then turns seven times clockwise and dunks him or herself thrice in the river. The ritual completed, they dry themselves, get dressed and chat with their neighbours before mounting back up the ghats and to home, breakfast and the day ahead. Most Westerners simply have never seen anything like this: massive morning prayer along the river Ganga.

Everything about Hinduism is a head-on challenge to western notions of religion and God. How many times have westerners (and Muslims) poked fun at the notion of thirty or three hundred million gods? Fixation on a precise number misses the point. Hindus are expressing the idea that God is infinite, that whatever they mean by God cannot be captured by any one idea, name or form. Thirty or three hundred or three million is merely another way of saying you can't count the ways in which God can be present. For Christians, Muslims or Jews - brought up to regard all forms of idolatry as heresy - this visible public display of bathing, faith and jubilation is therefore profoundly unsettling.

Same problem at Harishchandra and Manikarnika Ghats, the two cremation grounds, smack bang in the middle of the huge crescent of ghats, in full public view. This is something quite frankly that most people who have grown up in European and American cultures have simply never seen, where death is carefully hidden away in professional crematoriums and mortuaries. Indians, on the other hand, make a very public display of death. They bring their newly dead, wrapped in cloth, strung between bamboo litters carried through the crowded streets to the edge of the water. A cremation pyre is built, the body bathed in Ganga and then for several hours it will burn while relatives and priests chant and perform the prescribed rituals. In Varanasi death is the essence of public life of the city. That is what makes it powerful. This is also what makes it often incomprehensible to people seeing the city for the first time."