Guwahati: The Sustainable Development Forum Nagaland (SDFN) has expressed solidarity with the Adi people and other local communities in Arunachal Pradesh’s Siang valley opposing the proposed 11,000 MW Siang Upper Multipurpose Project (SUMP), calling on the state and central governments to withdraw additional armed security deployments from the affected areas, release detained protesters and initiate an independent inquiry into security forces’ excesses.

In a press statement, the Kohima-based forum said development projects must not compromise indigenous rights, ancestral lands, cultural heritage and ecological integrity. It expressed concern over escalating tensions in the Siang valley, citing the deployment of security forces, arrests and detention of community members, and restrictions on peaceful public mobilisation and expression.

“The Siang River is far more than a source of hydropower; it is an irreplaceable, living ecological and cultural lifeline that sustains communities, traditional livelihoods, extraordinary biodiversity, and sacred landscapes across the Eastern Himalaya,” the SDFN said.

While acknowledging the state’s responsibility to maintain public order, the forum said democratic rights, including peaceful assembly, freedom of speech and lawful dissent, must be respected and protected. It warned that administrative measures to suppress public concerns could deepen alienation and undermine democratic deliberations on a project of this scale.

The SDFN urged the Arunachal Pradesh and central governments to de-escalate the situation by withdrawing additional armed security personnel from affected areas and ending measures that restrict peaceful community gatherings.

It also called for a review of cases registered in connection with the SUMP protests, withdrawal of proceedings against community members, youths and leaders charged solely for exercising their right to peaceful dissent, and the prompt release of those it described as arbitrarily detained.

The forum further sought an independent inquiry into allegations of excessive force, unlawful detention, and harassment or intimidation of journalists, lawyers and civil society observers.

Referring to Article 19 of the Constitution, the SDFN said restrictions on movement and assembly must be lawful, necessary and proportionate, and that the rights to freedom of expression and peaceful assembly must be upheld.

The forum also urged the government to recognise the Adi people and other affected riverine communities as the primary custodians of their ancestral territories and rivers.

Citing the United Nations Declaration on the Rights of Indigenous Peoples, it said development interventions must follow the principle of free, prior and informed consent (FPIC). The SDFN maintained that no pre-feasibility report surveys, exploratory activities or subsequent project clearances should proceed without the explicit consent of affected communities.

The forum also called for independent ecological and seismic assessments before the project is taken forward, citing the Siang basin’s seismicity and ecological vulnerability.

“The Siang basin is situated in one of the most seismically active, ecologically delicate, and climate-vulnerable landscapes in the world. Mega-infrastructure here carries irreversible risks not only for upstream habitats and riverine ecology, but also for downstream communities across Assam and the wider Brahmaputra basin,” it said.

The SDFN urged the governments to subject the project to independent and transparent scientific scrutiny covering geological, seismic, hydrological and social impacts, with the findings made publicly accessible.

The forum said decisions concerning the future of rivers, forests and ancestral lands in the Northeast should involve local communities, adding that regional security and sustainability could not be achieved through top-down decisions that disregard local participation.

It also appealed to civil society networks, student organisations, research institutions and community bodies across Northeast India to express solidarity with the people of the Siang valley.