Sun Ratha, Ly Chandaravuth and Yim Leanghy are environmental activists and members of the organisation Mother Nature Cambodia. On 16 June 2021 they were arrested while investigating river pollution in the Tonle Sap river, charged with “plotting” and “insulting the King”, and sent to pre-trial detention. The environmental activist Seth Chhivlimeng was also arrested and later released after being detained for 24 hours. Evidence used against the activists reportedly includes recordings of private Zoom meetings. The arrests are deemed to be part of a pattern of intimidation against environmental defenders and Mother Nature's members in Cambodia. The group's campaigns includ efforts to overturn a planned hydropower project in the remote Areng Valley and expose the mining and export of sand from coastal area, which led to a total export ban on coastal sand in 2016.