The environment during the Mid-Tertiary comprised of tropical rain forest under oceanic climate and moderately hilly topography with about 2000 mm precipitation. Gradual increase in tropical deciduous elements, events of diastrophism, continentality of climate and immigration of conifers characterised Mid-Miocene to Pliocene. Cool and moist subtropical and temperate forest with precipitation from 1000–1500 mm were established in the western Himalaya during the early Pleistocene. Moist climate had continued during the Weichselian in the Kathmandu Valley, Nepal, but for the progressive aridity in the Kashmir valley, Rajasthan, Gujarat and Maharashtra since the Weichselian times. The evolution in the early hominids, the emergence ofHomo sapiensand the progressive evolution of the Palaeolithic, Mesolithic and Neolithic cultures were not governed by drastic changes in climate. The commencement of food production was circumstantial rather than induced by change in climate