The Deccan Plateau is a large plateau that covers most of South India.  It is triangular, surrounded by three mountain ranges.  It extends over eight Indian states (principally, Telangana, Maharashtra, Andhra Pradesh, Karnataka, Kerala and Tamil Nadu).

The plateau covers , 27.7 percent of India's landmass.

The uplands, areas of higher landmass, form a triangle that is nested in the familiar downward-pointing triangle of the Indian sub-continent's coastline. In the south of India, the plateau is largely over  above sea level. In the north it is mostly about  above sea level.  
The plateau is extremely large, and there are many habitats: different ecosystems with different sorts of vegetation, climate, geology and animals.  The forests on the plateau are older than the Himalayan mountains.

On the west of the plateau are the Western Ghats and in the east are the Eastern Ghats. These mountain ranges rise from their nearby coastal plains and nearly meet at the southern tip of India. The mountains make the southward-pointing vertex of a triangle.  The northern boundary of the triangle is made up by the Satpura Range and Vindhya Range. These northern ranges separate the plateau from the heavily populated riverine plains of northern India.

Origin of name 
The name is an anglicised from the Prakrit word dakkhin, which comes from the Sanskrit word dakṣiṇa- (), meaning 'South' or 'The South'.

The Deccan Traps 

The Deccan Traps are a main cause of the special geography and geology of South India. They are a large igneous province on the Deccan Plateau of west-central India (between 17–24N, 73–74E) and one of the largest volcanic features on the planet. They consist of multiple layers of solidified flood basalt that are more than  thick and cover an area of . The term 'trap', used in geology for such rock formations, is derived from the Dutch word for stairs, referring to the step-like hills forming the landscape of the region.

History 
The Deccan Traps formed between 60 and 68 million years ago, at the end of the Cretaceous period. The bulk of the volcanic eruption occurred at the Western Ghats (near present-day Mumbai) some 66 million years ago. This series of eruptions may have lasted fewer than 30,000 years in total. The gases released in the process may have played a role in the Cretaceous–Tertiary extinction event, which included the extinction of the non-avian dinosaurs. The consensus among the scientific community is that the extinction was triggered by the Chicxulub impact event in Central America but that the Deccan eruptions also disrupted the planet's climate.

Before the Deccan Traps region was reduced to its current size by erosion and plate tectonics, it is estimated that the original area covered by the lava flows was as large as 1.5 million km², about half the size of modern India. The present area of directly observable lava flows is estimated to be around .

The release of volcanic gases, particularly sulfur dioxide, during the formation of the traps contributed to contemporary climate change.  Data point to an average fall in temperature of 2 °C (3.6 °F) during this period.

References 

Flood basalts
Plateaus
Volcanoes of Asia
Mountains of India