Hun Vannak is an environmental rights defender and a former member of Mother Nature Cambodia, a movement opposing land-grabbing and defending environmental rights. In early 2020, the defender founded the youth movement Khmer Thavarak that advocates against social injustices and environment issues. On 13 August 2020, Hun Vannak and woman human rights defender Chhoeun Daravy were arrested for their participation in a peaceful protest in Phnom Penh. The defenders were part of a larger group of protesters who had gathered outside the municipal court to demand the release of human rights defender Rong Chhun, who was arrested for his labour and land rights advocacy campaigns.