A series of recent estimates by international nuclear watchdogs and reputed thinktanks hold that Pakistan has a total of 70 to 90 warheads compared to India's 60 to 80. China, in comparison, has around 240 warheads.
Even as global fears about the possibility of jihadis gaining access to Pakistan's nuclear arsenal, enriched uranium or technical know-how continue, its deadly inventory is only going to expand in the coming years.
Pakistan, after all, is supplementing its ongoing enriched uranium-based nuke programme with a weapons-grade plutonium one. Its two new heavy-water reactors being built at Khushab nuclear facility, with China's help, are clearly geared towards producing weapons-grade plutonium, as reported by TOI earlier.
In its latest annual world military expenditure report released on Wednesday, the Stockholm International Peace Research Institute (SIPRI) said Pakistan's weapons-grade plutonium production would jump seven-fold with the two new reactors at Khushab nearing completion.
"Our conservative estimates are that Pakistan has 60 warheads and could produce 100 nuclear weapons at short notice," said SIPRI, adding that Islamabad had earmarked its US-supplied F-16 fighters, Ghaznavi and Shaheen missiles as its nuke delivery systems.
India's nuclear weapons programme, in turn, has largely been plutonium-based, basically centred around the Pu-239 produced in research reactors like Cirus and Dhruva at Bhabha Atomic Research Centre.
Nuclear arsenals of India, Pakistan, and even China, pale in comparison to the gigantic ones of the two former Cold War foes, US and Russia. SIPRI estimates there are a whopping 22,600 active, inactive and stored nuclear warheads around the globe, enough to destroy it several times over.
While Russia has 12,000 warheads, 4,630 of them "deployed" ones, US has 9,600, which includes 2,468 of them operational. The two have, however, recently decided to slash their inventories by nearly one-third.
France comes third with 300, followed by UK with 225. Israel, which like India and Pakistan is not a signatory of the Nuclear Non-Proliferation Treaty, completes the list of the eight countries with nuclear weapons, with an arsenal of 80 warheads. Then, there is also North Korea, which has produced "enough plutonium for a small number of warheads", SIPRI said.
All these figures are not exact because countries keep their nuclear weapons programmes in thick cloaks of secrecy, which is only now being lifted by countries like US and UK.
India has been concerned about Pakistan's drive to bolster its nuclear arsenal over the past few years. While India has a clear and declared `no-first use' nuclear weapons doctrine, Pakistan has kept it vague to use as a tool to offset India's conventional military superiority.
Moreover, there is continuing controversy in India over whether the country has a credible thermonuclear or hydrogen bomb, given that a few experts contend the 45-kiloton thermonuclear device tested under the Pokhran-II tests in 1998 was "a fizzle".
The armed forces also remain quite worried about the lack of SLBMs (submarine-launched ballistic missiles) and ICBMs (intercontinental ballistic missiles) in their armoury, which are needed for a credible deterrent and for robust second-strike capabilities against both Pakistan and China.
At present, only the short-range Prithvi missile (150-350km) and the 700km range Agni-I have been fully operationalized till now. Agni-II (over 2,000km) and Agni-III (3,500km) are still in the process of being inducted by the Strategic Forces Command. India's most ambitious strategic missile Agni-V, with a 5,000km range, in turn, will be tested for the first time only by early-2011 or so.
Nuclear Warheads (Source: SIPRI)