Geography and Its Impact on South Asia’s Politics

South Asia is one of the most geographically varied regions on the planet, and that variety does far more than fill atlases. The mountains, rivers, plains, and seas that define this corner of the world have shaped where borders fall, how neighbours treat one another, and which conflicts keep resurfacing decade after decade. Stretching from the Himalayan peaks down to the coral atolls of the Maldives, the physical landscape here is tightly bound up with politics. To understand the diplomacy, the disputes, and the fragile cooperation between Bangladesh, Bhutan, the Maldives, Nepal, India, Pakistan, Sri Lanka, and Afghanistan, you first have to understand the land and water they share.

What makes South Asia a distinct region 🔗

South Asia is often called the Indian subcontinent, and there is a good geological reason for that. The landmass was formed when the Indian Plate collided with the Eurasian Plate, pushing up the highest mountain ranges in the world and leaving the region seismically active to this day. This collision created natural walls that separate the region from the rest of Asia, which is one reason South Asian civilisations developed with a strong identity of their own.

The region is bounded to the north by a chain of mountains: the Hindu Kush in the northwest, the Karakoram in the central north, and the Himalayas running along the rest of the northern edge. To the south, the Arabian Sea, the Bay of Bengal, and the Indian Ocean surround the subcontinent on three sides. Within these boundaries lie several distinct physical zones, and each one carries political weight.

The major physical zones 🔗

There are a few landscapes worth knowing well, because they recur constantly in regional politics.

The Himalayan belt forms the northern frontier. It separates India from China, Nepal, and Bhutan, and acts as both a defensive barrier and a contested line. The Indo-Gangetic plain is the fertile, densely populated heartland fed by the Indus and Ganges river systems, supporting hundreds of millions of people. The Deccan plateau covers much of peninsular India, older and drier than the northern plains. Finally, there are the island and landlocked states, including the island nations of Sri Lanka and the Maldives, and the landlocked countries of Nepal, Bhutan, and Afghanistan, whose geography heavily limits their strategic options.

How geography draws political boundaries 🔗

Natural features have always made convenient borders, and South Asia is a textbook case. The Himalayas form a natural divide between India and its northern neighbours. Rivers, mountain ridges, and coastlines were used by colonial administrators and later by independent states to mark out territory. As one widely used geography text notes, South Asia provides a clear example of how colonialism shaped current political borders, with many of today’s frontiers tracing back to lines drawn during British rule.

The problem is that physical features rarely match human realities cleanly. When the British partitioned the subcontinent in 1947, the new boundaries cut across river basins, communities, and farmland. Kashmir, sitting high in the mountains where India, Pakistan, and China meet, remains the most visible legacy of borders drawn without settled agreement. India shares either a land boundary or a maritime boundary with every other country in the region, which makes it the dominant geographic actor but also places it at the centre of nearly every territorial dispute.

Landlocked states and strategic dependence 🔗

Geography also creates dependence. Nepal and Bhutan are landlocked and, partly because of their terrain, remain relatively isolated in terms of physical geography and economic integration. A landlocked country relies on its neighbours for access to ports and trade routes, which gives the surrounding states considerable leverage. This is why Nepal’s relationship with India, and increasingly with China, is so sensitive. The mountains that protect these small states also fence them in.

Rivers: the lifeline and the flashpoint 🔗

If mountains divide South Asia, rivers tie it together, and that connection is both a blessing and a source of conflict. The Indus, the Ganges, and the Brahmaputra are the three great river systems, fed largely by Himalayan glaciers sometimes called the “Third Pole” of freshwater. These shared rivers are a source of livelihood for an estimated 900 million people across the region. When rivers cross borders, the question of who controls the flow becomes intensely political.

The Indus Waters Treaty 🔗

The most famous water arrangement in the region is the Indus Waters Treaty, signed by India and Pakistan in 1960 and brokered by the World Bank. The treaty divided the river system, giving the western rivers (the Indus, Jhelum, and Chenab) to Pakistan and the eastern rivers (the Ravi, Beas, and Sutlej) to India. For decades it survived even outright wars between the two countries. That stability changed when, in April 2025, India announced it would hold the treaty in abeyance following a terror attack in Kashmir, marking the first time tensions had genuinely disrupted the agreement.

The suspension shows how geography raises the stakes. Because the Indus flows through India before reaching Pakistan, India sits upstream and holds an advantage. But the same logic works against India elsewhere: on the Brahmaputra, India is the downstream country, dependent on cooperation from China. Analysts warn that weaponising water could weaken India’s own position in future negotiations and push neighbours like Bangladesh and Nepal closer to China.

The Ganges and the question of trust 🔗

Downstream of India lies Bangladesh, which depends heavily on the Ganges for agriculture, fisheries, and drinking water. The Ganges Water Treaty, signed in 1996, established a thirty-year water-sharing arrangement and recognised Bangladesh’s rights as a lower riparian state. That treaty is set to expire in 2026 and is now being renegotiated, and the outcome will test how India treats its smaller neighbours. India and Bangladesh share 54 transboundary rivers, including the long-disputed Teesta, so a single negotiation can ripple across many others. When a powerful upstream neighbour controls the tap, every downstream nation watches closely.

Maritime borders and the island question 🔗

Geography shapes politics at sea just as much as on land. The peninsular shape of the subcontinent and its long coastlines have produced several maritime disputes. The most persistent is Sir Creek, a roughly 96-kilometre tidal estuary in the marshlands between India’s Gujarat and Pakistan’s Sindh. The dispute is a legacy of colonial-era boundary demarcation and remains unresolved, partly because settling the creek’s boundary would determine the much larger maritime zone and the undersea oil and gas reserves beyond it.

The human cost is immediate. Fisherfolk on both sides are regularly arrested for accidentally crossing an unclear boundary. Some analysts argue the creek could become a template for environmental cooperation rather than conflict, since both nations share the same fragile delta ecosystem. For island states, the politics are different but equally tied to geography. Sri Lanka’s location astride major shipping lanes makes it strategically valuable, and the small island of Katchatheevu, ceded by India to Sri Lanka in the 1970s, periodically resurfaces as a sensitive issue in fishing rights and domestic politics.

Geography and the persistent security challenges 🔗

The same features that draw borders also create openings for conflict. Mountainous, porous frontiers are difficult to police, which feeds problems like cross-border terrorism, smuggling, and illegal migration. The rugged terrain along the Afghanistan-Pakistan border has long been hard for any central government to control. Long river deltas and marshy coastlines, like the area around Sir Creek, become corridors for drug smuggling and human trafficking when boundaries stay undefined.

Migration is closely linked to both geography and environment. Low-lying Bangladesh, sitting at the mouth of two great river systems, is acutely exposed to flooding, and population pressures combined with disasters drive movement across borders. These flows then become political flashpoints in neighbouring states. Security, in other words, is not separate from the landscape; it grows directly out of it.

Climate change and the case for cooperation 🔗

The newest and perhaps gravest challenge is climate change, and here geography makes the whole region interdependent whether its governments like it or not. The Himalayan glaciers that feed the Indus, Ganges, and Brahmaputra are melting. If warming continues, these glacier-fed rivers could see dramatically reduced flows in the long term, threatening the water supply of nearly a quarter of humanity. At the same time, devastating floods, like those that struck Bangladesh in 2024, are becoming more frequent.

This is exactly the kind of problem no single country can solve alone, because rivers and weather systems ignore political lines. Yet regional cooperation has weakened rather than strengthened. The South Asian Association for Regional Cooperation (SAARC) has been largely dysfunctional, hampered by India-Pakistan tensions, even though shared environmental threats arguably make collaboration more urgent than ever. There is a growing argument that water, energy, food, and the environment, all rooted in shared geography, offer a more promising basis for cooperation than the older security-driven agenda.

Why geography still decides so much 🔗

Pulling these threads together, a clear pattern emerges. The physical landscape of South Asia is not a neutral backdrop. The mountains decide which states are isolated and which are exposed. The rivers decide who holds power over whom and where treaties become weapons. The coastlines decide which resources are contested and which fishing communities suffer. And the changing climate is now rewriting all of these relationships at once, raising the cost of mistrust.

The countries of the region face a genuine choice. They can continue to treat shared geography as a zero-sum contest, where every river and border is leverage to be exploited. Or they can recognise that the same features binding them together also make cooperation a matter of survival. The land and water will not move. How the people who share them choose to respond is still open.

What do you think? Should South Asian countries treat their shared rivers as strategic assets to bargain with, or as common resources that demand joint stewardship? And if SAARC remains gridlocked, what kind of regional framework could realistically manage the climate threats that no single nation can face alone?

References

1. https://www.britannica.com/place/South-Asia
2. https://saylordotorg.github.io/text_world-regional-geography-people-places-and-globalization/s12-south-asia.html
3. https://pressbooks.pub/worldgeo/chapter/south-asia/
4. https://gulfnews.com/opinion/op-eds/why-treaties-have-not-ended-river-conflicts-in-south-asia-1.81886501
5. https://www.britannica.com/event/Indus-Waters-Treaty
6. https://scroll.in/article/1082319/indus-water-treaty-suspension-hydro-politics-will-have-dangerous-consequences
7. https://www.deccanherald.com/opinion/weaponising-indus-waters-treaty-is-a-strategic-mistake-3521599
8. https://vaidsics.com/current-affairs/sir-creek-site-of-decades-long-indiapakistan-border-dispute
9. https://www.stimson.org/2017/use-environmental-diplomacy-resolve-sir-creek-dispute/
10. https://theconversation.com/india-pakistan-conflict-over-water-reflects-a-region-increasingly-vulnerable-to-climate-change-256253
11. https://southasianvoices.org/environmental-diplomacy-to-resolve-sir-creek-dispute/