In the South Asian context, non-proliferation is not merely nuclear question. The larger forces and interests at work both within the  region and  outside have to be understood. Regional security cannot be considered in isolation from global or extra- regional conditions. The efforts have to be on two parallel lines. At the  global  level,  the  states in the  region have to participate in  the process to bring about a  truly legitimate and   non- discriminatory non-proliferation regime. At the regional level, efforts to build bridges of understanding among the countries in the region through confidence-building measures has to be sustained.  Hence, in South Asia, proliferation can best be achieved through a proper mix of global and regional approaches. Particularly, because of the awesome destructive potential of nuclear weapons their actual use is unthinkable. Even in low- level  nuclear combat with millions of fatalities there would  be no  winner, apart  from the doubtful survivability of crude weapons. It is more so in the case of close South-Asian neighbours like  India and  Pakistan.
Case of India and Pakistan
In case of both India and Pakistan national security concern has  been  the  principal factor in the  process of nuclearisation. Hostilities between the two countries have been there since partition in 1947.  The key territorial issue of Kashmir has its root  in  the colonial history of the sub-continent and  involved India, Pakistan and  China. India’s nuclear calculations are centered on China which has an expanding nuclear arsenal. While,  in  contrast, Islamabad’s  nuclear programme is  driven mainly by its threat perception and security concern with respect to India. Pakistan sees its potential nuclear forces as a deterrent to India’s conventional military advantages and   strategic ambitions. However, India, whose military build-up was spurred by its humiliating defeat in the 1962 war with China, viewed its nuclear programme as the vital component of a strategic plan to deter against a more powerful China. The nuclear chain in the world  has  been  rightly observed by John J. Schulz who  says, “The rationale presented by leading government officials in New Delhi and Islamabad to justify the current state of their weapons programme is analoguous to the  Ocean food chain –big fish eats little fish which  has  just eaten the  littlest fish. China created its nuclear deterrent with fears of Moscow and Washington in mind. China is feared by India and India is feared by Pakistan.  All three countries justify their present nuclear policies as a solution to security problems–a fully declared arsenal in China, a nuclear weapons option in India and now in Pakistan ‘an ability to assemble as the  equalising deterrent”.
Factor of nationalism
Next to security, nationalism  is  the propelling force of Indian and  Pakistani nuclear programme. This  is evident from the  national consensus in each  country on nuclear policy.  Both countries enjoy overwhelming domestic support to their nuclear programme. Nationalism has played a key role in shaping Indian politics since  Independence. Nehru championed self-reliance as part of India’s ‘‘neutralism” and New Delhi’s drive for indigenous science, technology  and  nuclear capability reflects that  self- reliance. The  Pakistani nuclear programme has  also  emerged as  the leading symbol  of Pakistani nationalism and   pride. According to a  retired Pakistani  Army General, it enjoys b i p a r t i s a n  a n d  p o p u l a r s u p p o r t a n d  i s  a b o v e  p o l i t i c a l controversy.  Pakistan’s  national interest demands that her nuclear capability to be  taken to its logical  conclusion.   As Islamabad emerged as  a  technological  leader of the Muslim World, its nuclear programme is  a  visible symbol  of Islamic technological sophistication and  power. In addition the desire to seek international respect and prestige is also an important incentive for nuclearisation in India and Pakistan. As one of the  world’s oldest and  most  populous civilisation, New Delhi  saw  the  acquisition of a nuclear weapon capability as the key to winning greater power status.
Effects of US policy in South Asia
In  South Asia,  one  of the cardinal principles of the US foreign policy  during past few  decades has  been  to deter the acquisition of nuclear weapons by  India and  Pakistan and  it has  made non-proliferation a central issue in bilateral relations with  them. Since  1974,  when India exploded its  first  nuclear device, successive US administrations have pushed for restraint by both countries, utilising a range of policy tools including diplomatic pressure, the  withholding of cooperation, embargoes on  the export of nuclear technology  and  the leverage of US assistance and  arms sales. In fact,  the  US has  sought to oppose proliferation in  South Asia  through all  available means at its disposal. Its goal  has   been   to inhibit the development or acquisition of such  system as  well  as  to prevent their use  or threatened use.  The  US  fear of a  nuclear exchange in  South Asia  is,  in  fact, outcome of nuclear theology  of the Western strategists which clearly state that nuclear weapons in the hands of non-nuclear and  developing nations has  greater possibility of their use.  
Apart from these, several factors make the pressure  of nuclear weapon capabilities on the sub-continent more posts dangerous than the  Super Power nuclear rivalry that preceded it.  Too many of the specific  conditions in the  region, including an asymmetrical balance of power, bitter personal remembrance, wars within living  memory border and  religious disputes and unstable and  highly emotional domestic constituencies point to the  need  for nuclear capability.