China secretly expanding nuclear warhead facilities just 800 km from Arunachal: Why India faces a tougher security calculus

FILE PHOTO: A member of the People's Liberation Army stands as the strategic strike group displays DF-5C nuclear missiles during a military parade to mark the 80th anniversary of the end of World War Two, in Beijing, China, September 3, 2025. REUTERS/Tingshu Wang/File Photo

China is rapidly expanding nuclear facilities in Sichuan, near India, boosting warhead production and testing. With over 600 warheads and rising, secrecy and military buildup raise concerns for India amid lack of global arms control and increased border tensions.

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China is quietly expanding its nuclear weapons infrastructure deep inside the mountains of Sichuan province, around 800 kilometres from Arunachal Pradesh. Satellite imagery analysed by experts and reported by The New York Times shows rapid expansion at secretive nuclear-related facilities that appear linked to warhead production and testing.

The developments come as China’s nuclear arsenal grows at an unprecedented pace. According to the latest estimates from the US Department of Defense, China possessed more than 600 nuclear warheads by the end of 2024 and is on track to cross 1,000 by 2030. This would make China the world’s third-largest nuclear power after Russia and the United States.

While Beijing claims its arsenal remains defensive, the scale, secrecy, and location of these upgrades raise serious concerns for India, especially given China’s parallel military activity near the Line of Actual Control.

Inside Sichuan’s nuclear valleys

The focus of recent scrutiny has been on two remote valleys in Sichuan province: Zitong and Pingtong. Both sites trace their origins to China’s Mao-era “Third Front” programme, which aimed to shield critical military industries from foreign attack by placing them deep inland.

After decades of reduced activity, these sites have seen renewed construction since around 2019.

Geospatial intelligence expert Renny Babiarz, who analysed the satellite imagery and shared it with the NYT, described the changes as “rapid growth.”

“The changes we see on the ground at these sites align with China’s broader goals of becoming a global superpower. Nuclear weapons are an integral part of that,” Babiarz said.

Zitong Valley and explosive testing

At Zitong, satellite images show new bunkers, fortified ramparts, and a complex with extensive piping that suggests the handling of hazardous materials. Experts believe the site is used to test high explosives that compress nuclear material to trigger a chain reaction in warheads.

“You have a layer of high explosives and the shock wave at the same time implodes into the centre. This needs blast tests to perfect them,” said Hui Zhang, a physicist at Harvard University’s Kennedy School of Government, as quoted by the NYT.

The testing area spans an oval space roughly the size of ten basketball courts, indicating large-scale experimentation rather than routine maintenance.

Pingtong and plutonium pit production

Pingtong appears even more sensitive. The double-fenced facility is believed to produce plutonium “pits,” the core components of nuclear warheads.

Its main structure features a 360-foot ventilation stack, a hallmark of plutonium handling facilities. Recent refurbishments include new vents, heat dispersers, and ongoing construction nearby.

Above the entrance, large Chinese characters display a slogan from President Xi Jinping: “Stay true to the founding cause and always remember our mission.”

Babiarz noted that Pingtong’s architecture closely resembles plutonium pit production facilities such as the Los Alamos National Laboratory in the United States.

A faster, quieter nuclear expansion

China’s nuclear growth is not limited to Sichuan. The buildup includes a massive laser ignition facility in nearby Mianyang, which could allow warhead research without full-scale nuclear detonations.

At the same time, Beijing has faced internal problems. The leadership of the People’s Liberation Army Rocket Force was purged amid reports of corruption and operational failures, including missiles allegedly filled with water instead of fuel. The reported fall of senior military figure Zhang Youxia has further highlighted dysfunction within China’s nuclear command structure.

Despite these issues, the expansion continues at speed and in secrecy.

“We don’t know how many warheads have been produced, but we just see the plant expansion,” Hui Zhang told the NYT.

Why this matters for India

Sichuan’s nuclear sites are far from coastal theatres like Taiwan but relatively closer to India’s eastern sector. This inland positioning reduces vulnerability to US strikes while keeping strategic depth against India.

Though unrelated on paper, China has simultaneously accelerated military infrastructure building near Arunachal Pradesh, including roads, airfields, and so-called civilian villages with dual-use potential.

For India, the concern is not just the number of warheads but the posture China is building. A larger, more survivable nuclear force gives Beijing confidence to apply pressure along disputed borders while believing it is shielded from escalation.

Former US official Matthew Sharp, now at the Massachusetts Institute of Technology, warned that the absence of transparency is dangerous.

“I think without a real dialogue on these topics, which we lack, it’s really hard to say where it’s going, and that, for me, is dangerous, because now we’re forced to react and plan around the worst-case interpretation of a concerning trend line,” Sharp said.

No arms control, rising risk

The timing makes matters worse. The last major US-Russia arms control treaty has expired, leaving no global framework to restrain nuclear expansion. Washington insists any future agreement must include China. Beijing has flatly refused.

US officials have gone further. Thomas G DiNanno, the US State Department’s under secretary for arms control, recently accused China of secretly conducting nuclear explosive tests. China denied the claim, calling it “untrue.”

For India, the message is clear. China is building quietly, rapidly, and without constraints. The combination of nuclear expansion, border militarisation, and political opacity creates a strategic environment where New Delhi must plan for worst-case scenarios.

China’s moves in Sichuan are not just about global power rivalry. They are part of a broader strategy that directly affects India’s security calculus, especially along a contested and volatile Himalayan frontier.