A long-forgotten Cold War operation in the Indian Himalayas has resurfaced, reviving concerns over a nuclear-powered device lost near Nanda Devi nearly six decades ago and its potential impact on the Ganga river system.
In 1965, amid heightened tensions over China&rsquo;s emerging nuclear programme, the US Central Intelligence Agency and India&rsquo;s Intelligence Bureau carried out a covert mission to install a high-altitude surveillance device on Nanda Devi, India&rsquo;s second-highest peak. The aim was to intercept radio signals related to Chinese missile and nuclear tests across the border.
The listening equipment was powered by a radioisotope thermoelectric generator (RTG) containing several kilograms of plutonium. RTGs generate electricity from heat released by radioactive decay and are commonly used in remote or extreme environments due to their reliability and long operational life.
The mission, however, was derailed by extreme weather. A severe blizzard forced the joint Indian-American team to abandon the device on the mountain and retreat. When climbers returned the following season to retrieve it, the RTG and its plutonium core had disappeared, believed to have been swept away by an avalanche or buried deep within the glacier.
Despite multiple search efforts by Indian and American teams over the years, the device has never been recovered. A 1978 survey by India&rsquo;s Atomic Energy Commission found no evidence of plutonium contamination in nearby rivers but was unable to determine the device&rsquo;s location, leaving its fate unresolved.
The issue carries long-term environmental implications because glaciers around Nanda Devi feed the Rishi Ganga and Dhauliganga rivers, which merge into the Alaknanda and Bhagirathi to form the Ganga. While experts say an intact RTG sealed within ice poses minimal immediate danger, they warn that damage to its containment due to glacier melt, landslides or flooding could release radioactive material into downstream water systems.
Concerns have intensified amid accelerating glacier retreat in the Himalayas, frequent extreme weather events and disasters such as the 2021 Chamoli flood. Environmentalists fear that climate-driven instability could eventually expose or disturb the remains of the device.
Although no radiation leak has ever been confirmed, the lost RTG remains a lingering reminder of how Cold War-era strategic decisions continue to cast a shadow over one of the world&rsquo;s most vital and sacred river basins.

Cold War-era CIA–IB mission left plutonium unit near Nanda Devi glacier

Lost Nuclear Device in Himalayas Raises Ganga Risk

Cold War-era CIA–IB mission left plutonium unit near Nanda Devi glacier

December 15, 2025 | 17:09 IST