By KK Chatradhara
The rapid expansion of hydropower projects in Arunachal Pradesh, which echoes the developmental trajectory of Himachal Pradesh, raises significant concerns about ecological sustainability in the fragile Himalayan region. Arunachal, endowed with 34% of India’s hydropower potential (50,328 MW), is advancing initiatives such as the 2,000 MW Lower Subansiri and 2,880 MW Dibang Multipurpose projects. Chief Minister Pema Khandu has highlighted the state’s aspirations, noting, “With 56,000 megawatts of hydro potential, Arunachal is rising, not only as the hydro capital of India, but as a beacon of how natural beauty and modern progress can walk hand in hand.” However, the 2025 monsoon disaster in Himachal Pradesh, which resulted in 94 fatalities and Rs 1,539 crore in damages, prompted a stern caution from the Supreme Court regarding the risks of unsustainable development. Arunachal has a critical opportunity to draw on Himachal’s experiences to ensure a balanced approach to progress and environmental stewardship.
Himachal’s challenges: a judicial call for caution
The 2025 monsoon in Himachal Pradesh brought devastating floods and landslides, claiming 94 lives, leaving 36 missing, and destroying 1,352 homes. The state’s 168 hydropower projects, intended as sustainable energy sources, inadvertently exacerbated the crisis through extensive deforestation, improper debris management, contributing to extreme weather events like cloudbursts. With only 10% deep forest cover remaining and 97.42% of the state prone to landslides, the Supreme Court, in its July 28, 2025,suo motu cognizance, issued a grave warning: “The state of Himachal Pradesh is on the verge of disappearing due to reckless, unscientific construction and unchecked hydropower proliferation.” The court underscored deficiencies in policy frameworks, environmental oversight, and forest conservation, urging immediate reforms to prevent further ecological harm.
Arunachal’s development trajectory
Arunachal Pradesh is chasing a similar path, with 150 planned hydropower projects across its 82% forested landscape, where 75% of the terrain is highly susceptible to landslides. The 2025 monsoon season resulted in 12 fatalities, impacted 33,000, and damaged critical infrastructures, signalling vulnerabilities similar to those in Himachal. Incidents such as the 2023 guard wall collapse at the Lower Subansiri project highlight geological risks, while the planned removal of 300,000 trees in Dibang Valley for the Etalin project threatens biodiversity and slope stability.
Climate change further heightens these challenges, with Arunachal facing a projected 1.8°C temperature rise by 2030, comparable to Himachal’s 1.6°C increase, intensifying monsoon variability and risks of glacial lake outburst floods (GLOFs), as witnessed in Uttarakhand’s 2013 disaster. The potential loss of species like the black-necked crane parallels Himachal’s declining western tragopan populations. Additionally, indigenous communities, such as the Idu-Mishmi’s and Adi’s, face displacement risks, echoing social tensions in Himachal’s Kinnaur area.
Shared challenges: a comparative perspective
The developmental paths of Himachal Pradesh and Arunachal Pradesh reveal striking parallels, underscoring the need for cautious, sustainable strategies. In Himachal, 168 operational hydropower projects, generating 10,519 MW, have significantly altered the landscape. Between 1980 and 2014, 90% of forest land was diverted into non-forest activities in Kinnaur division, reducing deep forest cover to just 10%, despite reported 66% forest cover, leaving 97.42% of the state vulnerable to landslides according to Geological Survey of India. In 2023, 163 landslides occurred, with 67 of 118 large projects at high risk due to construction on unstable terrain.
Arunachal, with plans for 150 projects to harness 50,328 MW, faces comparable risks. Its 82% forested landscape, with 75% prone to landslides, is already showing strain, as evidenced by the 2023 Lower Subansiri collapse, akin to Himachal’s geological failures. The planned felling of 300,000 trees in Dibang Valley mirrors Himachal’s Forest loss. While Arunachal’s 2025 monsoon was less severe (12 deaths, 33,000 affected), it signals a trajectory toward Himachal’s scale of disaster, with sediment-laden rivers flooding Assam’s plains, similar to Himachal’s impact on downstream rivers.
Charting a sustainable path forward
To align with the Supreme Court’s call for sustainable development and avoid Himachal’s ecological missteps, Arunachal must adopt a proactive, balanced approach. Comprehensive basin-wide environmental impact assessments, incorporating climate and seismic risks, are essential to address the cumulative effects of hydropower projects, a critical oversight in Himachal that drew judicial criticism. Unlike Himachal’s projects, which ignored river basin dynamics, Arunachal should adopt best practices, ensuring thorough evaluations before project approvals.
Preserving forest cover is paramount. Himachal’s loss of 90% of its forest land destabilized slopes, contributing to 163 landslides in 2023. Arunachal, with 82% of its land still forested, must implement stringent limits on deforestation, enforce debris management to prevent river siltation, and initiate reforestation to bolster slope stability, safeguarding ecosystems that support species.
Geological caution is another imperative. Himachal’s failure to map landslide-prone areas led to 67 high-risk projects, a mistake Arunachal can avoid by investing in advanced geospatial mapping to identify stable sites, steering clear of fragile zones like those exposed in the 2023 Lower Subansiri collapse. Reassessing hydropower strategies is equally vital. Himachal’s 168 large dams, criticized by the Supreme Court for “unchecked proliferation,” offer a cautionary tale.
Strengthening oversight is critical to address the regulatory gaps that plagued Himachal, as highlighted by the Supreme Court. Arunachal should establish independent monitoring bodies to enforce environmental standards, conducting regular audits to ensure compliance and prevent the laid-back assessments that fuelled Himachal’s crisis. These measures, rooted in Himachal’s hard-learned lessons, provide Arunachal with a roadmap to harmonize development with environmental and social priorities.
A shared Himalayan responsibility
Arunachal and Himachal stand at a critical juncture. Arunachal’s hydropower ambitions, articulated by Khandu, risk replicating Himachal’s ecological collapse, where 94 deaths and billions in losses exposed the consequences of unsustainable development. The Supreme Court’s warning of Himachal’s potential “disappearance” serves as an urgent call for Arunachal to embrace sustainable practices. By prioritizing demanding assessments, forest conservation, community engagement, and healthy oversight, both states can safeguard their Himalayan heritage and ensure a resilient future.
(The writer can be reach at kkchatradhara@gmail.com)
