Warming Himalayas Demand a Rethink: Hydropower and EIA

The Lift Line

“Every development activity in the IHR must be evaluated in light of the changing geological realities of the Himalayas.” (Archana Vaidya, The Hindu)

Why This Editorial Matters for Your Exam

This op-ed in The Hindu, published on 13 October 2026, is by Archana Vaidya, an advocate and the founder of the Forum for Environment Legal Policy Research (FELPR). She takes the deadly flood in Nepal’s Rasuwa district in August as a warning, and asks India to change how it clears projects in the Indian Himalayan Region (IHR): zone flood plains by valley slope, ban hydropower above a defined elevation, rethink the proposed Chenab-Beas link, and pause development until every project is reassessed.

For background, we covered the Rasuwa flood in three reports: the first account, the landslide dam on the Trishuli and why it was not a GLOF, and the case for cryosphere early warning in our editorial on avalanches and a Himalayan observatory network. Himachal’s own disaster governance is in our July editorial on Himachal landslides. This page stays on what the column adds: how projects are sited and cleared.

GS Paper 3: Disaster and disaster management; conservation, environmental degradation and environmental impact assessment; infrastructure (energy). GS Paper 1: Important geophysical phenomena; distribution of water resources. GS Paper 2: The role of the judiciary in environmental governance.

In the news: in The Hindu on 13 October 2026, Archana Vaidya argues that a warming, less stable Himalaya calls for slope-based flood zoning, a firm elevation limit on hydropower and a fresh environmental review of every project in the Indian Himalayan Region.

Background and Context

The Rasuwa flood the column starts from

⚠️ Geography check: the Lhende (Lende) Khola is a tributary of the Bhote Koshi of Rasuwa, which is the principal upper tributary of the Trishuli. The Trishuli rises at Gyirong in the Tibet Autonomous Region, where it is known as the Bhote Koshi, and joins the Kali Gandaki at Devghat in Chitwan. It is one of the seven major tributaries of the Gandaki system, which enters India as the Gandak. It is not the Bhote Koshi of Sindhupalchok, which belongs to the Koshi.

Not a GLOF, not an earthquake

A glacial lake outburst flood (GLOF) needs a glacial lake to breach. No such breach was established at Rasuwa: USGS classed the event as a glacial collapse and debris flow, and ICIMOD calls the trigger “suspected”. On cause, ICIMOD is careful: “it is too early to determine what role climate change played in this specific event.” Our report on why it was not a GLOF set out the difference.

What ICIMOD’s 2026 glacier outlook found

The HKH Glacier Outlook 2026 of the International Centre for Integrated Mountain Development (ICIMOD), launched in March 2026 for the World Day for Glaciers:

• found ice-loss rates across the Hindu Kush Himalaya “doubling since the year 2000”;
• drew on data from 38 monitored glaciers, only seven of which meet the World Glacier Monitoring Service benchmark;
• reported that between 1990 and 2020 HKH glaciers lost about 12 per cent of their area and 9 per cent of their ice reserves, and up to 27 metres of ice thickness since 1975;
• noted that the Karakoram, Sikkim, Zanskar and Bhutan “remain largely unmonitored”.

One of its authors, Mohammad Farooq Azam, put it this way: “We are trying to navigate a rapidly changing future with an incomplete map.”

The Himachal hydropower case the column cites

The Chenab-Beas link

The Analysis

1. A warning from next door. The author opens by noting that, for decades, the fight for “sustainable, climate-resilient, hazard-averse development” in the IHR has gone unheeded. She reads the Nepal floods as a sign that the “global natural commons”, from the Hindu Kush and Karakoram to the Himalayas, is in an existential crisis. She cites the IPCC and the World Meteorological Organization for a warming rate of 0.3°C per decade in the high mountains of Asia, nearly twice the global average. The firmer number on the page is ICIMOD’s: ice loss across the region has doubled since 2000. She also says Nepal, which she puts at roughly 0.1 per cent of global greenhouse gas emissions, “is paying the price for a crisis it did not create” and is right to demand compensation for loss and damage.

2. How warming loosens a mountain. The column explains the mechanism in steps. Meltwater pools on a glacier in supraglacial lakes and carves vertical shafts called moulins down to the bedrock, where a pressurised layer of water lubricates the glacier and lets it slide faster. Channels within the ice (englacial) and between the glacier and the bedrock (subglacial) then generate forces strong enough to fracture it. Lower down, permafrost, which the column defines as “ground or rock that remains at or below 0°C”, acts as “geological cement” in steep rock walls; as it thaws, rock avalanches, landslides and debris flows follow.

3. Rasuwa, and how to read the numbers. The column describes a block of ice and rock breaking off the northern flank of Langtang Himal and falling into the Lhende Khola, damming it until the dam broke. It calls the result “an inland tsunami” that travelled 170 km. Read these figures with care. Accounts of the runout differ: The Conversation has put it at “more than 170 kilometres” in one article and “almost 100 kilometres downstream” in another, and the Nepali Times has argued in print that the flood should not be called a “Himalayan Tsunami” at all. Researchers from the British Antarctic Survey did record unusually high ground temperatures two days before the collapse, and the fall was of around 1,200 metres. For the exam, hold on to the type of event: a glacial collapse and debris flow, with a cause still unconfirmed.

4. Mitigate, because you cannot prevent. “There is no technology to prevent such collapses,” the author writes, so the only option is to reduce their impact downstream. She lists the tools: regional cooperation with real-time data exchange, satellite and drone surveillance, acoustic and hydrological sensors on glacier-fed rivers, and continuous monitoring and, where feasible, engineered drainage of glacial lakes. The need for sharing is plain: as the Kathmandu Post reported, “Chinese monitoring systems had not detected a natural event on the Tibet side capable of producing a flood of this scale”. (We take up early warning in detail in our editorial on a cryosphere observatory.)

5. The core ask: change where and how we build. This is the column’s real contribution:

• Zone by slope. “Steeper slopes concentrate damage vertically, requiring infrastructure to be located much higher above the riverbed, while gentler slopes spread destruction horizontally, demanding an entirely different zoning approach.”
• A siting limit for hydropower. She calls for “a firm ban on construction above a defined elevation”. She says the Avay Shukla Committee and the Ravi Chopra Committee both recommended restricting major hydropower projects or subjecting construction above 2,200 metres to detailed expert review. The Himachal record we hold reads a little differently: the High Court asked the Shukla committee about projects above 7,000 feet, and the committee’s central recommendation was basin-wide EIAs with clearances withheld until they were done.
• Rethink the Chenab-Beas link. The rationale for diverting more water “may appear logical on paper”, she writes, but the project sits in a fragile Himalayan ecosystem and “its likely environmental impacts make it eminently avoidable”.
• A moratorium. Finally, “a moratorium on all development projects until each is rigorously reassessed for its environmental impact, hazard-averseness and climate resilience”.

These are the author’s recommendations, not government policy. The Chenab-Beas link remains a proposal.

Data and Institutions Vault

Prelims-grade facts:

The river:

• Lhende (Lende) Khola: a tributary of the Bhote Koshi of Rasuwa district, Nepal.
• Bhote Koshi (Rasuwa): the principal upper tributary of the Trishuli; the Trishuli rises at Gyirong in Tibet.
• Trishuli: one of seven major tributaries of the Gandaki; joins the Kali Gandaki at Devghat (Chitwan).

The event type:

• USGS: a seismic signal of magnitude 5.2, typed “landslide”; “no earthquake had occurred”.
• Glacial collapse and debris flow: not a GLOF, which needs a glacial lake to breach.

The glaciers (ICIMOD, HKH Glacier Outlook 2026):

• Ice-loss rates in the Hindu Kush Himalaya have doubled since 2000.
• 38 glaciers monitored; only seven meet the World Glacier Monitoring Service benchmark.
• 1990 to 2020: about 12 per cent of glacier area and 9 per cent of ice reserves lost.
• An ICIMOD-UNDP study found 3,624 glacial lakes across Nepal, India and Tibet; 47 potentially dangerous, 21 of them in Nepal.

Terms, as the column defines them:

• Moulin: a vertical shaft carved by meltwater through a glacier to the bedrock.
• Englacial and subglacial: water channels within the glacier, and between the glacier and the bedrock.
• Permafrost: ground or rock that remains at or below 0°C; in steep rock walls it acts as “geological cement”.

The court and the project:

• Court on its own motion v. State of Himachal Pradesh: a suo motu case in the Himachal Pradesh High Court on trees felled for hydel projects.
• Avay Shukla committee: recommended basin-wide EIAs for all river basins of Himachal, and a 5 km gap between projects.
• Chenab-Beas link (proposed): an 8.7 km tunnel through the Pir Panjal; barrage at Koksar on the Chandra, Lahaul and Spiti.

⚠️ Watch the trap:

• The Bhote Koshi of Rasuwa is the upper Trishuli, in the Gandaki system. The Koshi has a different Bhote Koshi, in Sindhupalchok.
• The Rasuwa flood was a glacial collapse and debris flow; USGS says “no earthquake had occurred”, and no lake breach was established.
• “7,000 feet” was a question the High Court put to the Shukla committee; “2,200 metres” is the author’s account of the committees.
• The Chenab-Beas link is a proposal, not a project under construction.

The Debate

How to Think About This

Break disaster risk into hazard, exposure and vulnerability. The author’s starting point is that the hazard cannot be stopped: “There is no technology to prevent such collapses.” So policy must work on the other two. Exposure is about where you build: elevation limits for hydropower and slope-based flood zoning. Vulnerability is about how you decide: a basin-wide, cumulative impact assessment that adds up every project on a river, instead of clearing them one at a time.

Keep three things apart in an answer: what the record shows (ICIMOD’s data, USGS’s classification, the High Court’s order), what the author recommends (a moratorium, a ban above a defined elevation, dropping the Chenab-Beas link), and what is still uncertain (the trigger at Rasuwa and the role of climate change). For GS4, the column is an argument for the precautionary principle: when the harm is irreversible and the science still settling, the burden falls on the project to prove it is safe.

Diagram-in-Words

Takeaway Box

• The argument: every development activity in the Indian Himalayan Region must be judged against its changing geology, with a moratorium until each project is reassessed.
• The hazard: ice-loss rates in the Hindu Kush Himalaya have doubled since 2000 (ICIMOD, 2026); thawing permafrost loosens steep rock.
• The event: the Rasuwa flood was a glacial collapse and debris flow, not an earthquake and not a GLOF; its trigger is unconfirmed.
• The levers: flood zoning by valley slope, a siting limit for hydropower, basin-wide cumulative EIA, and a fresh look at the proposed Chenab-Beas link.
• The record: the Avay Shukla committee recommended basin-wide EIAs for Himachal’s rivers; the High Court accepted the short-term recommendations prima facie.

Revision Flowchart

Sources: The Hindu, Archana Vaidya, “Warming Himalayas demand a rethink on development”; Down To Earth, on ICIMOD’s statement on the Trishuli flash flood; Kathmandu Post, Bhotekoshi flood; Kathmandu Post, ICIMOD glacier outlook; USGS event us7000tbwb; IFC, Trishuli cumulative impact assessment, chapter 3; Himachal Pradesh High Court order, 9 August 2010; SANDRP, Chenab-Beas link tunnel; The Conversation, satellite images of the Nepal flood; Nepali Times.

Source: Warming Himalayas Demand a Rethink: Hydropower and EIA — Ujiyari.com | Free UPSC & State PCS Editorial Analysis