It is the biggest bay on Earth—so big that five countries define the Bay of Bengal’s rim, among them India, the biggest country in the world by population, and Bangladesh, the eighth most populous. As such, the Bay of Bengal should be a natural and thriving economic space, binding South Asia and dynamic South-East Asia into one. But today it is a relative backwater. Ambitions are building to change that.

Elsewhere natural “macroregions”, a wonkish term beloved by planners, have cohered as reasonably powerful blocs: for example Europe, North America and South-East Asia itself, with its Association of South-East Asian Nations (asean). But following post-colonial independence in the late 1940s, India, Bangladesh (first as part of Pakistan), Sri Lanka and Burma (now Myanmar) turned inward. Protectionism and even animosities rose.

Compared with other blocs, the trade that the Bay of Bengal’s countries conduct today with the outside world is paltry, despite being near one of the world’s busiest business shipping routes. Worse, they trade alarmingly little among themselves: only just over 6% of their total trade, compared with about 23% for asean. The regional economy is fragmented.

However, change is under way. Constantino Xavier of the Centre for Social and Economic Progress, a Delhi-based think-tank, describes a “race to correct the fragmentation”. The impetus comes from India, says Ali Sabry, Sri Lanka’s foreign minister. It is motivated by a desire not only to foster regional development but also to counter China’s own efforts to increase its influence in its backyard.

Combined with this, Bay countries now mostly understand that connectivity and trade are key to prosperity. One indication is a splurge of infrastructure spending on ports, power and the like: from the construction of Bangladesh’s first deep-water port at Matarbari at the top of the Bay to the vast expansion of Colombo port, which sits on major trans-ocean shipping routes, at the bottom. The Matarbari project—which is the largest in Bangladesh—is backed by the Japan International Co-operation Agency (jica), a body charged with development assistance. One part of the Colombo port is being developed by China; another by India’s Adani Group, along with American development financing.

Meanwhile India’s government is leading an attempt to revive the group charged with helping develop a regional economy. Founded in 1997, bimstec (short for the Bay of Bengal Initiative for Multi-Sectoral Technical and Economic Co-operation) includes the five Bay countries, plus Bhutan and Nepal. It is poorly staffed, while initiatives run into the sand for lack of interest or consensus. Only recently did it adopt a basic charter. But hopes in some quarters are now rising that its summit in Bangkok in September—the first in two years—will see greater co-operation.

In many places, change can already be glimpsed. Tomohide Ichiguchi, jica’s head in Bangladesh, reckons the country’s main transport bottlenecks will be sorted within a few years. (jica is also involved with improving links with Bhutan, Nepal and land-locked north-eastern India.) And obvious gains from improved cross-border energy trade are starting to be reaped. For instance, India is selling increasing amounts of power to Bangladesh from West Bengal, while Bhutan and Nepal are starting to sell their abundant hydropower to India.

Grounds for scepticism remain. In 2007 the Asian Development Bank laid out a plan that detailed the road, rail and port links needed to boost regional connectivity. For years the plan gathered dust. Neighbours neglected to inform each other of infrastructure projects, let alone co-operate on them. A failure to bring down barriers to trade is another problem—import tariffs not only provide tax revenues but an opportunity for corruption.

And even if the political will is found for deeper integration, two huge challenges loom. The internal one is Myanmar. It is the natural link between South Asia and Thailand and the rest of South-East Asia. But the country is at war with itself. The benighted junta in charge has neither the appetite nor the expertise to think about long-term planning.

Water works

The other challenge is geopolitics. The Bay of Bengal is an important place in the rivalry playing out across the Indo-Pacific. For example, China is increasingly interested in Myanmar as a way to get access to the Indian Ocean. The Chinese government also seeks to spy on rivals’ navies: that is one reason why India is exercised about the possibility of Chinese radar stations being built on Myanmar’s Coco Islands and in Sri Lanka. Even if its member-states find greater means to co-operate, contestation also looks set to become a permanent feature in the Bay of Bengal.