This work is an attempt to understand the complexities of the environmental history of Kerala from ancient till the modern period. A major transformation in the environment of Kerala happened with the British colonial rule. They introduced a new forest policy, which collected maximum timber from the Western Ghats for further advancement in the British empire. Colonial forest policies were almost similar in the colonial district of Malabar and the princely states of Cochin and Travancore. They were engaged in mono-crop plantations in the ecologically fragile hills and game hunting in the forest regions of Kerala. Later agrarian migration inside Travancore and Cochin, and the large-scale settlement of people in Malabar from Central Travancore also drastically changed the land use pattern in Kerala. The 'Grow More Food' campaign of the government in the post-independent period and other support of the government and non-governmental agencies assisted small scale farmers to reclaim the uncultivated land in the highlands for the extensive expansion of agriculture. However, the environment of Kerala also underwent drastic changes due to the urbanization process. The state began to experience environmental crisis with the great flood in Munnar in 1924.