The Comprehensive Test Ban Treaty (CTBT) (1996) was looked at as the most important means to tackle both, horizontal and vertical proliferations of nuclear weapons. It claimed 

(a) Constrained the development and qualitative improvement of nuclear weapons

(b) End the development of advanced new types of nuclear weapons

(c) Contribute to the process of nuclear non-proliferation and the process of nuclear disarmament

(d) Strengthen international peace and security. 

India linked the signing of the CTBT with a time bound global disarmament programme. Indian view was that the Non-Proliferation Treaty (NPT) had failed to tackle the question of global nuclear disarmament and the CTBT with its implicit limitations on its scope and also did not proceed in the direction of the goal of disarmament. India maintained that the five nuclear weapon powers should agree on a timetable for total removal of nuclear weapons as a precondition to its acceptance.  EU is signatory of NPT hence the nuclear relation between EU and India is always questioned.  India considers the NPT a discriminatory document. The EU desires India to sign both the NPT and the CTBT. 

As the relations of India with Pakistan and China are not peaceful, and both neighboura are armed with nuclear weapons; India can not stop its defence nuclear programme as well as put them under the supervision of five nuclear power countries. India instead went ahead and conducted a series of nuclear tests and declared its status as a nuclear weapon power in May 1998. US and Japan imposes sanctions on India and put pressure on India to sign CTBT. The EU strongly condemned the Indian nuclear tests, but refrained from imposing any sanctions.  However, UN Security Council has urged Indian government for signing of CTBT to make nuclear free south Asia. 

Later India grows technically and economically, developed countries started stating that it is India's sovereign right to decide how to ensure its security and to which treaty may she signed. India gone beyond the CTBT and has signed joint initiatives/pacts for peaceful use of nuclear technology with Russia, USA, France and even with Japan. Indian, though not signatory of NPT or CTBT has pronounce her "No First Use" policy of nuclear weapons. The nuclear arm race in south asia and bagaband proliferation of nuclear program in North Korea and Iran has given a chance to developed countries for enforcement of CTBT and ban on nuclear technology for defence use. India has approaches to become member of The Nuclear Supplier Group (NSG) that manage the trade of nuclear material and manage to get the fissile materal for its nuclear based power plants.  Being not a signatory of NPT or CTBT, Australia has declined the India's request for supply of nuclear material.