Cambodia's environmental issues fall into two primary categories: the management or mismanagement of natural resources and problems with pollution and sanitation in its growing urban areas.
Cambodia has the third highest rate of deforestation in the world, motivated by timber harvest as well as clear-cutting for agriculture. Deforestation destroys habitats and disrupts the balance of delicate tropical soils. Without trees holding the soil in place and replenishing organic matter with leaf litter, the soil erodes quickly and loses much of its fertility in the first few years of cultivation.
Cambodia's coastal ecosystems, many of which are mangrove forests that provide important spawning grounds for fish and protection from floods, are threatened by several factors. Coastal ecosystems are being choked by sediment washed loose from recently deforested areas inland. These waters also carry hazardous pesticides and fertilizers. Poorly regulated shrimp farms cause mangroves to be cleared and release excess nutrients into the water, resulting in the overgrowth of algae and disruption of the ecosystem.
As Cambodia industrializes, people flock to urban areas, which are growing too fast for sanitation infrastructure to keep up. Many areas have no sewer systems, or they're dysfunctional at best. Sewage and industrial effluent are contaminating groundwater and surface water in many urban areas. Hazardous solid waste often finds its way to open landfills where it can leach into groundwater or be blown by the wind.