From Buddha’s Smile to Nasr: inside India-Pakistan nuclear rivalry

In 1974, India conducted its first nuclear test, dubbed 'Smiling Buddha'. Although officially described as a "peaceful" test, it sparked global anxiety and led to the creation of the Nuclear Suppliers Group, which imposed stringent restrictions on nuclear cooperation with New Delhi.

Over subsequent decades, India's nuclear aspirations were met with external pressure and sanctions, particularly following Bhabha's death and amid domestic political instability. Nonetheless, India pressed ahead, developing its nuclear infrastructure and launching parallel missile and uranium enrichment programmes in the 1980s, led by scientists such as A.P.J. Abdul Kalam and Rajagopala Chidambaram.

By the 1990s, India had accumulated the materials and components necessary to construct several nuclear bombs, although it refrained from further testing. This changed in 1998 when the Bharatiya Janata Party returned to power under Prime Minister Atal Bihari Vajpayee, who boldly proclaimed India's right to possess nuclear weapons as a "sovereign prerogative" and a "defensive necessity".

On 11 and 13 May 1998, India conducted five nuclear explosions, including a thermonuclear (hydrogen) bomb. These devices—labelled Shakti-1 to Shakti-5—were tested in utmost secrecy to avoid detection by American satellites. Following the tests, Vajpayee proudly declared India a fully-fledged nuclear power. The international backlash was swift. The US, Japan, and others imposed immediate economic sanctions. China voiced concern about a potential nuclear arms race in the region.

Pakistan's quick response

Neighbouring Pakistan, India's long-standing rival, wasted no time in responding. On 28 May 1998, it conducted a series of detonations in the Chagai Hills, officially entering the nuclear club. This was not merely a show of strength, but the culmination of a journey sparked by one of the most traumatic episodes in Pakistan's history: the secession of Bangladesh in 1971.

Pakistan's nuclear pursuit began on 20 January 1972, when Prime Minister Zulfikar Ali Bhutto convened top scientists and engineers in Multan, declaring that Pakistan must achieve nuclear parity with India. His message was unequivocal: "We will eat grass if we must, but we will get one of our own (atom bomb)."

Nuclear physicist Munir Ahmad Khan, who had returned from the International Atomic Energy Agency, was appointed to lead the Pakistan Atomic Energy Commission. However, the commission soon encountered technical challenges, particularly in producing fissile material. It was then that metallurgical engineer Abdul Qadeer Khan entered the fray. With experience in uranium enrichment facilities in the Netherlands, Khan brought back vital knowledge and technology.

With full government support, Khan established the Kahuta Project, later Pakistan's primary nuclear research hub. Alongside the Atomic Energy Commission, this dual-track approach enabled the production of highly enriched uranium by 1984—an achievement Khan confirmed in a letter to General Muhammad Zia-ul-Haq.

The 1990s were decisive. In the same month as India's nuclear tests in 1998, Pakistan detonated five nuclear devices in the Chagai Desert, followed by a sixth test in the Kharan Desert two days later. Pakistan thus became the world's seventh nuclear-armed state—a move that intensified regional tensions and drew condemnation from the UN Security Council through Resolution 1172.

How their arsenals compare

Since both countries joined the nuclear club, debates have persisted about their respective capabilities and who holds the upper hand. Although both conducted nuclear tests in the same month of the same year, technological disparities between their programmes have existed from the start and continue to this day.

India's programme has relied on plutonium extracted from research reactors—a more advanced approach allowing for refined weapon design. Pakistan, by contrast, has depended on highly enriched uranium from the Kahuta facility via centrifuge technology. Plutonium enables more compact, efficient warheads, albeit with greater engineering complexity and handling risks.

India is believed to have worked on thermonuclear bomb designs, as stated during its 1998 tests, though questions remain over whether a full thermonuclear detonation was achieved. Such bombs utilise nuclear fusion triggered by fission, yielding vast explosive power. Pakistan has confined itself to fission-based weapons and a few 'boosted' variants, and has yet to claim thermonuclear capability.

The difference between plutonium and uranium bombs lies in the fissile material and the detonation mechanism. Uranium bombs—like that dropped on Hiroshima—use uranium-235 in a relatively simple 'gun-type' design, fusing two sub-critical masses. This method is easier but requires substantial highly-enriched uranium.

Plutonium bombs—like the 'Fat Man' dropped on Nagasaki— use plutonium-239 and a complex 'implosion' design, compressing the plutonium with synchronised conventional explosives. Though more compact and potent, these bombs require sophisticated engineering due to plutonium's instability. Nevertheless, modern warheads generally favour plutonium.

India has built a diverse arsenal including medium- and long-range ballistic missiles and nuclear-capable submarines, providing full triad capability—land, sea and air. Pakistan's missile arsenal, though formidable, is narrower in range and scope, centred around rapid-response systems such as the Shaheen and Ghauri.

According to the Arms Control Association, India holds approximately 172 nuclear warheads, compared with Pakistan's 170. Despite near parity in numbers, significant differences in doctrine, technology, and strategy render this balance fragile.

India maintains a declared 'no first use' policy, pledging nuclear retaliation only in response to a nuclear attack. However, some Indian officials have hinted at revisiting this stance. Pakistan categorically rejects this doctrine, reserving the right to pre-emptive use in the face of existential threats.

Islamabad considers tactical nuclear weapons, like the short-range Nasr missile, as crucial to halting an Indian advance during a conventional conflict, especially given its inability to match India's numerical and logistical might.

Advantage India

India's conventional military superiority is pronounced, boasting over 1.24 million active troops against Pakistan's 560,000. New Delhi has earmarked a massive $415.9bn defence budget for 2025-2029, focusing on modernisation and reduced import dependency. Pakistan, hampered by domestic and border concerns, is projected to spend $10bn by 2028.

India leads in air power, operating over 220 Russian Su-30MKI fighters and 36 French Rafale jets. Pakistan relies on Chinese JF-17 and J-10C fighters and legacy American F-16s, seeking to bridge the gap through its alliance with Beijing.

On the ground, India fields a mixed fleet of Russian T-90s, indigenous Arjun tanks and modern artillery like the K9A1. Pakistan relies heavily on Chinese tanks, such as the Al-Khalid and VT-4, and uses American M109 howitzers. Air defence in India benefits from Russian S-400 and Israeli Barak-8 systems, while Pakistan employs Chinese HQ-9 and LY-80 systems to narrow the gap.

India's navy is equally formidable, featuring two aircraft carriers, nuclear-powered submarines, and an array of destroyers and frigates. Pakistan's naval force is comparatively modest, lacking carriers and relying on ageing French Agosta submarines and Chinese frigates.

In addition to its superiority in both air and naval forces, and its wider network of military bases and installations, India's advantage—ironically and alarmingly—stands as one of the main reasons behind Pakistan's firm adherence to the early nuclear strike option.

Islamabad views the use of tactical nuclear weapons, such as the short-range Nasr missile, as possibly the only means to halt a potential Indian advance in the event of a conventional war, particularly given its inability to match India's numerical and logistical dominance.