While India pursued a solely “peaceful nuclear program” in the 1950s, by the mid-1960s it reconsidered its aversion to nuclear weapons in the face of escalating regional instability. India’s two main rivals in the region have been Pakistan and China.
In November 1964, Prime Minister Lal Bahadur Shastri authorized theoretical work on the Subterranean Nuclear Explosion for Peaceful Purposes (SNEPP). India commissioned a reprocessing facility at Trombay, which was used to separate out the plutonium produced by the CIRUS research reactor. This plutonium was used in India's first nuclear test on May 18, 1974, described by the Indian government as a “peaceful nuclear explosion.” An expert analysis of the explosion demonstrated India’s capability to produce nuclear weapons.
The Indian arsenal is estimated to consist of around 100 nuclear warheads, mostly of a low yield fission variety. India has a declared nuclear no-first-use policy and continues to advocate the end to nuclear testing and global disarmament “based on the principles of universality, nondiscrimination and effective compliance.”
India carried out a series of nuclear tests in 1974 and 1998 which led to criticism and sanctions, but since then, then sanctions have largely been lifted and the United States has quietly accepted India's possession of nuclear weapons so long as no further tests are carried out.
In 2006, the US-India Nuclear Deal was signed as the two countries sought for the United States nuclear industry to enter commercial tasks on building nuclear reactors in India. Two concerns-inspections and the liability for a nuclear accident-were spoken about in depth. The deal has been held up for 8 years, yet American suppliers are already facing competition from Russia and France who are also building nuclear energy reactors in India.
Recently, a naval nuclear arms race between India and Pakistan has formed. Assured retaliatory capability, sea-based deterrent vis-a-vis China, and Pakistan's nuclear ambitions are some of India's motivations in this race.
On April 24, 2014, the Republic of the Marshall Islands filed a lawsuit against India at the International Court of Justice for violation of customary international law regarding the obligation to negotiate for an end to the nuclear arms race and for nuclear disarmament. The case is expected to last into at least 2016.