Physicist Rajagopala Chidambaram, who played a pivotal role in designing India’s nuclear weapons programme and worked with defence scientists to shape the country’s nuclear arsenal and deterrence philosophy, died on Saturday. He was 88.

Chidambaram was the chairman of the Atomic Energy Commission (AEC) when India, under the leadership of Prime Minister Atal Bihari Vajpayee, tested five nuclear bombs near Pokhran, Rajasthan, in May 1998 and declared itself a nuclear weapons state.

Chidambaram passed away in Jaslok Hospital in Mumbai, a PTI report said, citing an atomic energy official. He is survived by his wife Chella and daughters Nirmala and Nithya.

After retiring from the atomic energy department, Chidambaram served as the principal scientific adviser (PSA) to the government from 2001 to 2018, a period during which he also steered multiple initiatives spanning energy, healthcare and strategic technology self-reliance, among others.

Prime Minister Narendra Modi, in a post on X, described Chidambaram as “a key architect” of India’s nuclear programme who had made “ground-breaking contributions in strengthening India’s scientific and strategic capabilities”.

Congress leader and former environment minister Jairam Ramesh, in a post on X, cited Chidambaram’s pivotal roles in the country’s first nuclear test in 1974 and the 1998 tests. “Educated entirely in India, he had a formidable global reputation in nuclear physics,” Ramesh wrote.

Chidambaram, who had studied in Chennai and the Indian Institute of Science, Bangalore, before joining the atomic energy department, was only 31 when his senior Raja Ramanna, a physicist at the Bhabha Atomic Research Centre (BARC), asked him to begin work on nuclear weapons.

“I was surprised when he asked me to take up this work because this was a completely different field from what I was working on,” Chidambaram wrote in India Rising, his memoir co-authored with former colleague Suresh Gangotra in 2023. The memoir recounts how Chidambaram and his colleagues slept in a military truck while transporting plutonium for the nuclear device to Pokhran for the 1974 test.

Twenty-four years later, Chidambaram — working with colleagues in the BARC, the atomic energy department and the Defence Research and Development Organisation — supervised the tests that would draw the veil off India’s nuclear weapons programme.

The 1974 test had plunged India into a regime of technology denial with other countries deciding to deny multiple technologies critical in the development of strategic technologies, including nuclear weapons. Chidambaram steered the programme through that regime, calling the denial a “technology
boon” for it compelled India to develop critical technologies on its own.