What he required for karst topography to form?

Karst topography forms primarily through the dissolution of soluble bedrock, such as limestone, gypsum, or salt, by natural acidic water, often from rain or groundwater. This process requires a combination of geological conditions, including the presence of these soluble rocks, adequate rainfall, and a landscape that facilitates water movement. Over time, the dissolution creates distinctive features like sinkholes, caves, and underground rivers. Additionally, vegetation can play a role by enhancing the acidity of the water through organic decay.