There are few places left on Earth where one can still watch the planet manufacturing life in real time. Along India’s northeastern frontier, where watershed succeeds watershed, river succeeds river, and one ecosystem seamlessly yields to another, the Earth continues to function much as it always has, governed by water, forests, gravity, and time. Here, the hand of man is present but not dominant. An occasional Indian or Chinese post clings to life amidst an overwhelming wilderness, but it is nature that remains the principle architect, shaping every valley, every river and, once we descend below the tree line, every forest according to rhythms established long before our species arrived.
Stand here for a while, if only in your imagination, and look carefully. Streams tumble from impossible heights before gathering strength and eventually becoming mighty rivers. Glaciated lakes, each a different colour and hue, lie scattered across the landscape like fragments of another world. Forests stretch for miles upon miles, and human settlements become sparse interruptions in an otherwise uninterrupted canvas. Nature does not whisper here. It speaks loudly, and sometimes even bellows, reminding us that this is how the Earth should have been and, in many ways, how parts of it must remain if these vast catchment areas are to continue sustaining life far beyond the horizon.
The McMahon Line
Perhaps I should explain why this article occasionally meanders, for the frontier does that to you. One moment, you are looking at a glacier and the next, you are thinking about the coastal regions of Bengal and Bangladesh, the continental shelves that surround the Indian peninsula, or of a child who may never physically see these mountains and yet whose future will be shaped by them. That is because nothing here exists in isolation. The rivers born in these mountains eventually nourish the plains of Assam, contribute to one of the largest delta systems on the planet, and ultimately influence life thousands of kilometres away in the oceans that surround the Indian subcontinent. The northeastern frontier, in that sense, is not remote at all. It is intimately connected to every one of us.
The McMahon Line itself has acquired an almost mythical status over the decades, often reduced in public discourse to a contested line drawn upon a map. Yet that is perhaps the least interesting thing about it. Running broadly along the great watershed that separates the Tibetan plateau from the river systems that descend into India, it is geography in its purest expression. Politics may have given it a name, but the mountains had already established the logic. Caravans lumbered across the few mountain passes, maintaining tenuous links between the roof of the world and the valleys below, carrying not just trade, but cultural and religious ideas that would eventually shape entire societies.
Others before us had recognised this magic. Frank Kingdon Ward, Captain Bailey and Captain Morshead had themselves ventured into these immense landscapes, often returning with more questions than answers. They understood that the frontier rarely reveals itself fully to any one generation, and that every journey merely adds another brushstroke to a much larger canvas.
My own relationship with these mountains began almost accidentally in 1961 and, over the decades, work and circumstance repeatedly drew me back to this extraordinary corner of India. Looking back, I now realise that those journeys were never the story itself. They were merely preparing me to see the frontier differently.
Perhaps that is the greatest gift that flying bestows upon us. Mountains cease to become destinations, and instead reveal themselves as systems. Rivers are no longer blue lines on maps but living arteries connecting one world to another. Distances collapse, relationships emerge, and geography itself begins to tell a story.
Uncovering the Protagonist
Between 2008 and 2011, while producing the Northeast Trilogy, I was once again given generous helicopter support by the Indian Army. Yet government directives of the day understandably required us to maintain a respectful distance from much of the actual watershed. We complied, but from my perch in the sky I had already seen enough to know that another story remained untold. Beyond those ridgelines lay something extraordinary and, for the next 15 years, that unfinished chapter quietly refused to leave me alone.
Fate, however, occasionally rewards persistence. Lieutenant General K.T. Parnaik, who had been the Corps Commander at Tezpur during the making of the Northeast Trilogy, eventually became Governor of Arunachal Pradesh, and discussions began on producing three large format books on Western, Central and Eastern Arunachal Pradesh. Once that project gathered momentum, I approached the Chief of Defence Staff, General Anil Chauhan, an officer deeply invested in India’s geographical frontiers, and requested helicopter support so that the story could finally be told in its entirety.
What unfolded during February and March 2026 was nothing short of extraordinary. Over 50 hours of flying time, using both the nimble Cheetah and HAL’s Advanced Light Helicopter, we traversed the frontier from the IndoBhutan-Tibet Trijunction in the west to the Indo-Myanmar-Tibet Trijunction in the east. Yet this is not a story about helicopters. The machines merely provided a seat from which to watch the Earth at work.
Almost imperceptibly, the sorties revealed that the mountains are not the protagonists at all. The rivers are. The mountains merely provide the paper upon which water writes its story.
The Nyamjang Chu river first revealed itself at Khinzemane before being joined by the Nam Ka Chu at the base of the Thagla Ridge, forever etched into India’s military consciousness. The Mago Chu becomes the Tawang Chu before eventually surrendering itself to larger systems further downstream and ultimately becoming part of the Manas basin. Then comes the immense drainage system of the Kameng, known as the Bhairali once it enters Assam, before the Upper and Lower catchments of the Subansiri are assembled by rivers such as the Kurung and Kamey. Further east, the Yargyap Chu and the Siyom gather the melting waters in the Menchuka and Bokar regions before the Siyom, still a haven for golden mahseer, eventually surrenders its identity to the Siang.
It is astonishing to think that until 1935, no one knew with certainty that the Siang was in fact the upper reaches of the Brahmaputra, for the great Yarlung Tsangpo seemed to vanish somewhere near the great bend around Namcha Barwa. For centuries, even Hindu mythology had bestowed the honour of being the principal source upon the Lohit further to the east. Such was the mystery that enveloped these mountains, and perhaps still does. We have become so accustomed to believing that everything has already been discovered that we sometimes forget how recently some of these great geographical quandaries were resolved.
Sometimes the best way to observe nature is not to follow it constantly, but to step back, remain patient, and allow the forest to speak for itself.
The Wild Green Earth
Then the drama intensifies as human settlements all but disappear. Take the Army out of the equation and a place like Mipi, which dominates maps of the region, is barely a settlement with half a dozen families. As I photograph as much of the terrain as I can, the vast Dibang basin spreads beneath us, its tributaries descending from Andra La and Yonggyap La before surrendering themselves to the Dibang river. The Dri arrives from Aguia La, and below us stretch the immense forests of the Dibang Wildlife Sanctuary, home to the Mishmi takin Budorcas taxicolor taxicolor. Waterfalls seem to descend from every conceivable direction and even beauty, one begins to feel, has to have its limits.
Then comes the Lohit itself, entering India at Kibithu before flowing past Walong and Hayuliang and beginning yet another chapter at Parshuram Kund as it debouches into Upper Assam. Beyond, the geography changes once more. The mountains lower themselves, moisture deepens, and the great forested ridges of the Naga Patkai begin their long sweep southwards. In the Northeast Trilogy, I had once taken the Noa Dehing to be the dividing line between the Assam Himalaya and the Patkai mountains, but that was more a matter of convenience than geography. Almost as if protesting our intrusion, a dozen hornbills explode from the canopy below us. Namdapha has always had this effect. It reminds us that while we may think we are observing nature, nature itself is busy observing us. Forty years ago, with Bittu Sahgal expecting me to return with footage of hoolock gibbons and clouded leopards for Sanctuary Films, in leech-infested terrain where I could barely see my hand ahead of me, I had seen the underbelly of these forests. Today, from the air, I was seeing their magnificent crown.
There is another transition that gradually reveals itself from the air. Above the tree line, one encounters a harsher world of rock, ice and sky where life clings on in remarkable ways. Yet as one descends, almost imperceptibly at first, colour returns. A lone shrub becomes a thicket, a thicket becomes a forest, and suddenly an entirely different world explodes into existence.
This is the Wild Green Earth. Not wilderness in the conventional sense, but the Earth functioning largely as it always has, governed by water, altitude, sunlight and time. Perhaps that is what we are really trying to preserve. Not a landscape frozen in time, but a process that has allowed life to continuously reinvent itself. For these forests are not static entities. They are living systems, forever advancing, retreating, adapting and evolving, reminding us that resilience, rather than fragility, may be nature’s greatest gift.
There was, however, another dimension to this journey, perhaps the most sobering of all. Unlike many others, I was not seeing these landscapes for the first time. I was revisiting them. Over three decades, whether in 1991, 2000, 2011 or now in 2026, I have repeatedly returned to these mountains at roughly the same time of the year. The geography remained unchanged, but the mountains themselves had altered in a manner that was impossible to ignore.
Change is Here
In the past, these frontiers were almost invariably draped in snow. This year, what was terrifyingly stark was the extent to which some of the highest ranges had shed that familiar mantle. Kangto, Gorichen, and even mountains deep inside the Pemako region of Tibet displayed remarkably little snow. Further east, Dapha Bum stood almost entirely devoid of snow and ice. The Himalaya, whose very name translates as the abode of the snows, increasingly appeared in shades of black, brown and grey.
Perhaps this is where Alan Paton enters the story. I studied him in school and recalled his writing almost 80 years ago in Cry, the Beloved Country, wherein he observed how rich green hills eventually break down owing to human and cattle interference, changing colour as they lose their ability to sustain life. From standing unshod upon rich matted grass to suffering lacerations in the feet as the hills themselves begin washing away in streams of red earth, one cannot help but think of those words while flying above these mountains.
Yet one must also exercise caution. Change itself is a fundamental component of evolution and these mountains, among the youngest on Earth, have always been in a state of becoming. It would be simplistic and arrogant to attribute every transformation solely to climate change. What concerns us is not change itself, but the pace and scale at which some of these changes now appear to be unfolding, and the possibility that humanity is increasingly becoming one of the variables influencing the equation.
What concerns us is not change itself, but the pace and scale at which some of these changes now appear to be unfolding and the possibility that humanity will influence the equation.
Their changing appearance reminded me of a traffic light transitioning from green to red. Perhaps we presently inhabit that brief and uncertain moment when the traffic signal hesitates at amber before an altogether different reality reveals itself. The message itself is neither fatalistic nor apocalyptic. Nature has always possessed a remarkable ability to reinvent itself. Our task is not to control that process, but to ensure that we do not become the force that interrupts it.
There is another thought that remained with me long after the rotors had fallen silent. Both the Indus and the Brahmaputra originate in the vicinity of Lake Mansarovar. One sets off westwards as the Yarlung Tsangpo begins its long journey east. For hundreds of kilometres both remain relatively placid, gathering themselves gradually as countless streams join them along the way. Then something remarkable happens. The Indus encounters the great Nanga Parbat massif while the Tsangpo finds itself at the base of Namcha Barwa. Both mountains rise to 7,620 m., two markers at either end of the great Himalaya. Both rivers then perform an almost identical manoeuvre. They swing around these colossal bastions in great loops before abruptly changing direction and cutting southwards into the Indian subcontinent. One cannot help but marvel at such asymmetry. What hand can create such elegant imbalance and yet produce such extraordinary harmony? Perhaps that is the lesson these mountains have been trying to teach us all along. Nature does not seek symmetry. It seeks balance.
Perhaps that is why this frontier cannot let go. It is not asking to be conquered, photographed or even admired. It is asking to be understood. For in these mountains, rivers and forests, the Earth is not offering us a warning so much as a lesson. Evolution is not a finished process. It is still at work. The great challenge before us is not to preserve these landscapes in amber, but to ensure that we do not overwhelm the systems that have perfected themselves over millions of years. If we can do that, perhaps the rivers will continue to write their stories, the forests will continue to reinvent themselves, and the mountains, however altered their appearance may become, will continue to remind us that balance, and not symmetry, is nature’s greatest achievement.