Indigenous communities protest toxic river pollution in Thailand's Kok River

Thailand's northern communities escalate calls for action against river contamination

Hundreds of villagers, Indigenous leaders, environmental defenders, monks, and activists completed a six-day Peace Walk along the Kok River in July to demand urgent action against worsening water contamination. The protest highlighted concerns that the river, which supports generations of communities, is becoming increasingly unsafe due to transboundary pollution.

The Kok River flows from Myanmar’s Shan State through Thailand’s Chiang Rai and Chiang Mai provinces before joining the Mekong. It provides drinking water, irrigation, fisheries, transportation, and cultural identity to riverside communities. However, residents now fear these lifelines are threatened by heavy metal contamination linked to upstream mining operations in Myanmar.

The Peace Walk, one of the largest recent demonstrations on the issue, urged the Thai government to strengthen cross-border cooperation, investigate contamination sources, and protect communities dependent on healthy river ecosystems. Concerns have grown following reports of elevated arsenic and other heavy metals in rivers flowing from Myanmar into northern Thailand. Environmental groups and local communities attribute the contamination to expanding rare earth and mineral mining operations in Myanmar, reportedly financed by Chinese investors.

The pollution extends beyond environmental damage. Farmers rely on river water for irrigation, while fishing communities depend on healthy aquatic ecosystems for food and income. Public health authorities have advised caution regarding the consumption of river fish and other aquatic animals due to heavy metal exposure risks.

Civil society organizations warn that contamination now affects not only the Kok River but also the Sai, Ruak, Salween, and Mekong rivers. According to the NGO Coordinating Committee on Development (NGO-COD), turbidity has increased dramatically along sections of the Thai-Myanmar border, while arsenic and lead levels have exceeded safety thresholds in several communities.

Because these rivers cross national boundaries, downstream communities often bear the consequences of activities beyond Thailand’s control. Environmental advocates argue that stronger regional cooperation between Thailand, Myanmar, and China is necessary to investigate pollution sources, improve monitoring, and prevent further contamination.

Public frustration has grown alongside perceived inaction. On July 6, members of the People's Network to Protect the Kok, Sai, Ruak, and Mekong Rivers marched toward the Chinese Consulate-General in Chiang Mai to deliver a petition urging China to regulate companies operating mines in Myanmar. Police attempted to block the protest, leading to a confrontation where two demonstrators were injured—a broken arm and a dislocated shoulder. Protesters filed a complaint alleging excessive force, while police stated officers acted within legal procedure. One injured demonstrator, Wisarut Srichan, is considering legal action against the police.

Two days later, civil society groups gathered outside the Chinese Embassy in Bangkok to demand action on water contamination and condemn the Chiang Mai police response. They called for an independent investigation into the use of force and urged authorities to identify investment networks and businesses responsible for environmental harm and human rights violations.

Activists said they did not expect violence, as the march was small and authorities had been notified in advance. However, environmental defenders in Thailand face additional threats beyond physical confrontation. Human rights organizations have documented the increasing use of Strategic Lawsuits Against Public Participation (SLAPPs) against community leaders, journalists, and activists who raise concerns about development projects.

One notable case involved environmental defender Sumeth Rainpongnam, who faced a 50-million-baht (USD 1.5 million) lawsuit while advocating for community environmental rights. Rights groups argue such legal actions discourage public participation and make it harder for affected communities to voice environmental concerns.

For Indigenous communities in northern Thailand, protecting the Kok River is inseparable from safeguarding their lands, livelihoods, and cultural heritage. Karen and other Indigenous groups have long opposed projects they believe threaten forests and river systems. In Omkoi District, Karen villagers challenged a proposed coal mining project, arguing that environmental impact assessments failed to consider Indigenous knowledge and local ecosystems. Communities have also opposed the Yuam–Salween Water Diversion Project, citing concerns over its impact on forests, fisheries, and water resources, as well as insufficient consultation with affected communities.

These efforts reflect a broader understanding of environmental stewardship among Indigenous peoples. Many view rivers not merely as resources to be exploited but as living ecosystems vital to culture, food systems, and future generations.

Participants in the Kok River Peace Walk emphasized that communities with generations of riverside experience possess valuable ecological knowledge that should guide conservation efforts. They called for stronger recognition of Indigenous land rights, meaningful community participation in environmental decisions, transparent monitoring, and greater protection for environmental defenders.

As northern Thailand grapples with transboundary pollution, residents argue that protecting the Kok River requires more than emergency responses. It demands sustained regional cooperation, corporate accountability, and greater recognition of Indigenous stewardship that has long helped safeguard the region's rivers.

For those who completed the Peace Walk, protecting the Kok River is about defending public health, cultural survival, and the rights of future generations to inherit safe, living rivers free from contamination.