Pakistan tests nuclear capable Shaheen 1A missile

In 1962, India suffered heavy casualties in the Sino-Indian war.

In 1964, China tested nuclear weapons and by 1968, demonstrated full thermonuclear capability. This was the primary driver for India to begin testing nuclear weapons technology.

India's first successful nuclear weapons test was in 1974, under Indira Gandhi.

Pakistan subsequently began ramping up its own nuclear weapons technology with assistance from China.

Reports emerged in the 1980s, that China had given Pakistan design specifications for a fully tested nuclear weapon.

Pakistan was a crucial supply line for US forces in Afghanistan during the Cold War, so the US turned a blind eye to Pakistan's nuclear weapons program.

This also marks the phase when control over Pakistan's nuclear weapons program was taken over by the military.

India conducted five nuclear weapons tests from 11-13 May 1998, under Prime Minister Atal Bihari Vajpayee, and declared itself a nuclear armed nation.

Pakistan subsequently demonstrated its nuclear capabilities in six tests conducted from 28-30 May 1998.

In 1999, the Kargil conflict broke out, but neither country used nuclear weapons despite issuing numerous threats to do so, demonstrating first-hand the concept of nuclear deterrence.

A nuclear weapon requires a delivery system to be a credible threat.

These systems comprise of aircraft, ballistic missiles, ships and submarines.

The range and physical maneuverability of these delivery systems determines their potency.

Countries try to diversify their delivery systems to maintain a credible deterrent posture. If one system is compromised due to an attack, the other must be available for retaliation.

Pakistan currently has 110-130 nuclear warheads.

Pakistan has eight land-based missile systems of which five are SRBMs and three are MRBMs.

Pakistan's F-16 and Mirage-III planes make up the backbone of their nuclear delivery system.

In 2012, the Pakistani navy established the Naval Strategic Forces Command for development and deployment of a sea based nuclear force. Pakistan does not have sea launch capability yet.

India has 110-120 nuclear warheads.

India has six land-based ballistic missiles of which two are SRBMs, one MRBM and three IRBMs.

India also has three sea launched ballistic missiles, of which 2 are SRBMs and one MRBM.

The Indian Air Force's Mirage 2000 and Jaguar planes are the primary delivery mechanisms, while an unknown number of submarines carry nuclear warheads as well.

India's nuclear doctrine defines a strict 'no first use' policy.

It further states that India will use all its nuclear forces in full scale, for a "massively disproportionate response" to a nuclear attack.

Pakistan defines spatial, military, economic and political thresholds which will evoke a nuclear attack.

These include heavy casualties on the Pakistani military, or economic and political interference in Pakistan's policy making.

With the development of Pakistan's Shaheen III missile, all major Indian cities are within striking range of Pakistani nuclear weapons.

India's Agni III ensures full coverage of Pakistan's land mass as well.

However, since Pakistan does not possess sea-launch capability yet, India's submarine-launched K-15 Sagarika missile ensures that India has the upper hand in the Indo-Pak nuclear deterrence scenario, despite having fewer nuclear warheads.

Pakistan successfully test fired the Shaheen 1A, a nuclear capable Short Range Ballistic Missile (SRBM) with a a range of 900 km.

Last week, Pakistan conducted the second test of the Shaheen III Medium Range Ballistic Missile (MRBM) with a range of 2750 km, bringing all major Indian cities within striking distance.

Pakistan does not have Intermediate range or Intercontinental ballistic missile technology yet.