On Son Island in Vietnam’s Mekong Delta, Le Trung Tin scatters fish feed into his ponds, where dozens of snakehead fish leap through the surface in synchronised bursts. “I taught them how to do that,” he says proudly, tossing another handful of feed at his fish.

The scene looks idyllic, but Le’s fish farm is a reluctant response to an escalating crisis. For decades, he made his living fishing the Hau River, a distributary of the Mekong. But in recent years, plastic waste clogged his nets and strangled the fish. “I had no choice but to stop,” he says. “Everything was tangled – trash, nets, even the fish themselves. It was hopeless.”

In his speech on the world’s struggle against poverty at the 19th G20 Summit in Rio de Janeiro in November 2024, China’s President Xi Jinping, cited his country’s standout track record of wealth creation, and exulted: “If China can make it, other developing countries can make it too.

China’s promise to guide the Global South on the path toward modernization has included support for green and sustainable development. Yet its pledge also holds a central environmental challenge, especially as the share of global greenhouse gas emissions from emerging markets and developing economies continues to increase. 

In spring 2024, I travelled in the Mekong Delta with Vietnamese researchers to investigate the country’s dwindling mangroves. 

One day while hiking along the coastline of Bac Liu Province in southern Vietnam, we came across the remains of a once-flourishing mangrove forest now littered by countless concrete blocks. My colleagues noted that the decades-long trend of disappearing mangroves here seemed to be unstoppable. 

During a visit to Vietnam in November 2023, I cringed as my aunt tossed our now empty bánh mì plastic bag onto the sidewalk. “It doesn’t really matter,” she shrugged, “there aren’t any nearby trash cans anyway.” Finding a trash can wouldn’t have helped much, as two-thirds of Vietnam’s plastic waste ends up burnt, landfilled, or leaked.

As the COVID-19 pandemic reached all corners of the world, countries rapidly introduced a series of containment policies to stop its spread, including school and workplace closures, restrictions on gathering size, and limits to population movement. In contrast to complete or partial border closures for foreign nationals, restrictions on population movements within one’s country have received much less attention, despite the fact that most countries introduced restrictions on internal migration during the pandemic in the form of bans on inter- or intra-provincial travel, or partial or complete lockdowns. With over 300 million internal migrants in India and 261 million in China (out of an estimated 760 million internal migrants worldwide), these barriers to mobility are particularly acute in Asia. But are they effective?

In the Mekong region, there is a general push to strengthen water data management and ultimately make evidence-based infrastructure development and water resources management decisions. The efforts of the region’s governments and development partners will ideally help mitigate the cumulative impacts of infrastructure development on water resources; save lives, livelihoods, and property from potentially devastating floods and droughts; and help natural resources be used sustainably. The challenge will involve navigating potential pitfalls related to technical know-how and harmonization of standards as they develop effective water data sharing platforms.