The Palaeolithic Age in India is divided into three phases in accordance with the type of stone tools used by the people and also according to the nature of climatic change.
The first phase is called Early or Lower Palaeolithic, the second Middle Palaeolithic, and the third Upper Palaeolithic.
Until further and adequate information is available about the Bori artefacts, the first phase may be placed broadly between 600,000 and 150,000 BC, the second between 150,000 and 35,000 BC, and the third between 35,000 and 10,000 BC.
However, between 35,000 and 1500 BC, tools relating to both Middle and Upper Palaeolithic ages have been found in the Deccan Plateau.
The Lower Palaeolithic or the Early Old Stone Age covers the greater part of the ice age. The Early Old Stone Age may have begun in Africa around two million years ago, but in India it is not older than 600,000 years. This date is given to Bori in Maharashtra, and this site is considered to be the earliest Lower Palaeolithic site. People use hand axes, cleavers, and choppers. The axes found in India are more or less similar to those of western Asia, Europe, and Africa. Stone tools were used largely for chopping, digging, and skinning.
Early Old Stone Age sites have been found in the valley of river Son or Sohan in Punjab, now in Pakistan. Several sites have been found in Kashmir and the Thar desert. Lower Palaeolithic tools have also been found in the Belan valley in UP and in the desert area of Didwana in Rajasthan. Didwana yielded not only Lower Palaeolithic stone tools but also those of the Middle and Upper Palaeolithic ages. Chirki-Nevasa in Maharashtra has yielded as many as 2000 tools, and those have also been found at several places in the south.
Nagarjunakonda in Andhra Pradesh is an important site, and the caves and rock shelters of Bhimbetka near Bhopal also show features of the Lower Palaeolithic age. The rock shelters may have served as seasonal camps for human beings. Hand axes have been found in a deposit of the time of the second Himalayan inter-glaciation, when the climate became less humid. The people of the Lower Stone Age seem to have principally been food gatherers. They took to small game hunting and lived also on fish and birds. The Early or Lower Stone Age in India may be associated with the people of the Homo sapiens group.
The Middle Palaeolithic industries were largely based upon flakes or small pieces of stone which have been found in different parts of India with regional variations. The principal tools comprise blades, points, borers, and scrapers, all made of flakes.
The geographical horizon of the Middle Palaeolithic sites coincides roughly with that of the Lower Palaeolithic sites. The artefacts of this age are found at several places on the river Narmada, and also at several places, south of the Tungabhadra river. The Belan valley (UP), which lies at the foothills of the Vindhyas, is rich in stone tools and animal fossils including cattle and deer. These remains relate to both the Lower and Middle Stone ages.
In the Upper Palaeolithic phase we find 566 sites in India. This may be due to the general presence of grassland dotted with few trees. The climate was less humid, coinciding with the last phase of the ice age when the climate became comparatively warm. In the world context, it marks the appearance of new flint industries and men of the modern type (Homo sapiens).
In India, we notice the use of blades and burins, which have been found in AP, Karnataka, Maharashtra, central MP, southern UP, Jharkhand and adjoining areas. Caves and rock shelters for use by human beings in the Upper Palaeolithic phase have been discovered at Bhimbetka, 45 km south of Bhopal. An Upper Palaeolithic assemblage, characterized by comparatively large flakes, blades, burins, and scrapers has also been found in the upper levels of the Gujarat sand dunes.