All the following are environmental hazards except

The environmental hazards are the natural phenomena or human activities that cause harm to the environment and human health. Flooding and vulcanicity are environmental hazards because they can cause damage to property and life. Deforestation is also an environmental hazard because it can lead to soil erosion, loss of biodiversity and other negative impacts on the environment. However, afforestation is not an environmental hazard, as it refers to the process of planting trees and creating forests, which helps to mitigate the negative effects of deforestation and other environmental hazards. Therefore, the answer is "afforestation".