PAKISTAN released Indian fisherman captured in disputed waters as a goodwill gesture when India celebrated Independence Day.

Releasing fisherman has become a common practice on the subcontinent to signal readiness for improved bilateral relations.

Other atmospheric confidence-building measures or CBMs are the release of political prisoners, cultural and sporting exchanges, and the provision of humanitarian assistance after natural disasters. These steps are always welcome, but they have not led to breakthroughs in the past.

Atmospheric CBMs can be unilateral or reciprocal. They are informal and usually do not require complicated implementation procedures. Prior to the 2008 Mumbai attacks, New Delhi initiated more atmospheric CBMs than Islamabad. Since the Mumbai attacks, Islamabad has initiated more goodwill gestures than New Delhi.

Atmospheric Pakistani and Indian CBMs may occur, on average, two or three times annually, although after a severe crisis, more than a year might pass without a single gesture to improve bilateral relations. Atmospheric CBMs are particularly useful to signal readiness to improve relations after a severe crisis.

In May 2003, 12 months after the 2001-2 ‘Twin Peaks’ crisis, New Delhi released 70 Pakistani fishermen and 60 political prisoners. These initiatives followed prime minister Atal Behari Vajpayee’s remarks in Srinagar that, “We once again extend the hand of friendship but it should be reciprocated by both sides”.

President Pervez Musharraf and prime minister Zafarullah Khan Jamali welcomed these gestures, joining India in restoring diplomatic ties.

Prime Minister Manmohan Singh has employed atmospheric CBMs often, including the offer of help after the 2010 millennial floods — 20 months after the 2008 Mumbai attacks. President Musharraf also employed atmospheric CBMs, starting in 2003, one year after the Twin Peaks crisis subsided.

President Asif Ali Zardari has continued this practice, including the release of Indian fishermen in September 2010 shortly after New Delhi offered flood aid to Pakistan. In 2011, Islamabad released prisoners before and after high-level talks. In June 2012, Islamabad released hundreds of fishermen and an Indian national convicted of spying and imprisoned for nearly 30 years. The frequency of atmospheric CBMs suggests that they require minimal investment of political capital by national leaders. In contrast, formal CBM agreements on military- and nuclear-related matters are infrequent occurrences.

Atmospheric measures have not typically facilitated formal measures, and both types of CBMs have not prevented severe crises. Those who seek to prevent cumulative gains from CBMs by carrying out mass-casualty attacks have succeeded in doing so.

Formalised nuclear- and military-related CBMs between India and Pakistan require a much higher threshold of political will and capital. Military-related CBMs have accompanied the advent of nuclear weapon capabilities on the subcontinent. They are usually prompted by crises.

Formal CBMs serve multiple purposes. They are useful in controlling escalation during periods of heightened tensions, they demonstrate responsible nuclear stewardship, and they reassure domestic and foreign audiences after crises have passed.

Formal military and nuclear-related CBMs have been in finalised in 1988 (non-attack pledges against nuclear installations and facilities), 1991 (airspace violations and advance notifications of certain military exercises), 1992 (prohibiting chemical weapons), 2005 (advance notifications of ballistic missile flight tests and the creation of a hotline between maritime security agencies), and 2007 (nuclear accidents).

In 2011, the ballistic missile flight test and nuclear accident measures agreements were extended. A 2003 ceasefire agreement along the international border and the Kashmir divide falls somewhere between a formal CBM and an atmospheric measure.

This is a meagre list of accomplishments for a quarter-century of diplomatic engagement. In the same timeline, the United States and the Soviet Union went from a fierce nuclear arms competition to deep cuts in nuclear forces.

Other military-related CBMs between Pakistan and India can easily be envisioned — such as a cruise missile flight test notification agreement, an incidents at sea agreement, and a withdrawal from current positions on the Siachen Glacier — but the timing is not yet ripe for these accords. High-level efforts are now focused on trade and economic investment. In September 2011, India and Pakistan announced plans to increase bilateral trade. Pakistan granted Most Favoured Nation status to India soon thereafter, and Manmohan Singh announced his intention to move towards a Preferential Trade Agreement with Pakistan.

Some weeks ago, New Delhi decided to allow Pakistani citizens and companies to invest in economic sectors other than defence, atomic energy, and space. India is improving facilities for trade at the Attari crossing, and promises have been made to liberalise visa regimes.

These CBMs are encouraging, but if past is prologue, they will encounter the usual delays by cautious civil servants and by spoilers who will try to disrupt them.

The connective tissue between atmospheric CBMs and formal military- and nuclear-related measures is weak. Adding economic measures to this mix might provide greater adhesion and concrete results — but not without concerted and persistent efforts by national leaders.

Michael Krepon is co-founder of the Stimson Centre, where Drew Stommes is an intern.