Western Ghats

The Western Ghats, also known as the Sahyadri in much of their northern and central extent, form the elevated western rim of the Deccan Plateau and adjoining peninsular uplands. They are commonly described as a mountain range, but much of their physical identity comes from an escarpment: a high plateau edge with a steep seaward face and a broader, more gradual descent toward interior India.

This asymmetry distinguishes the system from a narrow chain built around one central crest. The western flank is deeply cut by short valleys that fall toward the Konkan, Kanara, and Malabar coastal lowlands. East of the divide, rolling uplands and long river valleys merge into the Deccan interior.

The Ghats extend roughly north to south through Maharashtra, Goa, Karnataka, Kerala, and Tamil Nadu. The northern end lies near the Tapi valley, while the southern sectors continue through the Nilgiri, Anaimalai, Palani, and associated highlands toward the tip of the peninsula. The distance from the escarpment to the coast varies: in some places steep slopes rise close to the coastal plain, while elsewhere foothills and low plateaus create a wider transition.

The range is broadly continuous but not unbroken. Passes and gaps provide lower crossings through the escarpment, and the Palakkad Gap forms the largest interruption between the Nilgiri Hills to the north and the Anaimalai Hills to the south. Farther north, corridors such as the Thal and Bhor gaps cut through the Sahyadri section. These openings connect the western coastal lowlands with the interior plateau and locally alter drainage, airflow, and relief.

The Western Ghats are not a single fold belt. Their modern relief developed along the western margin of the Indian Peninsula as continental separation, faulting, uplift, and long erosion shaped the edge of the plateau beside the Arabian Sea. Rivers and slope processes then cut valleys, scarps, and isolated high blocks into that raised margin.

Rock type changes along the range. Thick basalt flows of the Deccan Traps dominate much of the northern section, producing stepped slopes, flat-topped uplands, and resistant cliffs. Farther south, ancient gneiss, charnockite, granite, and other crystalline rocks underlie rounded massifs, steep valley walls, and high plateaus. The southern Ghats contain the greatest elevations, including the Nilgiri, Anaimalai, and Palani highlands.

The Western Ghats form one of peninsular India's principal drainage divides. On the seaward side, rivers such as the Mandovi, Zuari, Sharavati, Netravati, and Periyar descend over relatively short distances to the Arabian Sea. Their steep gradients produce narrow valleys, rapids, and waterfalls where resistant rock or escarpment steps interrupt the channel profile.

East of the divide, the gentler plateau slope supports much longer drainage networks. Headwaters and tributaries of the Godavari, Krishna, and Kaveri systems gather runoff from the Ghats and carry it across the peninsula toward the Bay of Bengal. Seasonal monsoon rainfall drives strong changes in discharge, while upland soils, weathered rock, valley storage, and reservoirs affect the timing of flow beyond the wet season.

During the southwest monsoon, moisture-bearing air from the Arabian Sea reaches the western face of the Ghats and is forced upward. Cooling and condensation bring heavy rainfall to many windward slopes and crest zones, especially where the relief is high and directly exposed to onshore flow. Rainfall still varies substantially with latitude, elevation, slope direction, and the position of gaps.

Beyond the crest, descending air contributes to a broad rain shadow across parts of the Deccan Plateau. The contrast can be sharp over a relatively short distance: humid coastal and windward terrain gives way to drier interior basins and uplands. Higher elevations are also cooler than surrounding lowlands, and the largest gaps allow some maritime air to pass eastward with less topographic lifting.

The Western Ghats connect several major physical regions. Their steep seaward front borders the narrow western coastal plains and the Arabian Sea drainage, while their inland slope merges with the Deccan Plateau and the upper basins of large east-flowing rivers. Sediment and runoff move away from the crest in both directions, but the length and gradient of the western and eastern river systems differ markedly.

In the south, the Ghats join the Nilgiri and adjoining highlands, where western and eastern peninsular upland systems approach one another. Within Geography Atlas, the Western Ghats belong in the Mountain Hub as a plateau-edge range that can be compared with the more fragmented Eastern Ghats. Together, the two records show contrasting ways in which old highlands organize the margins and drainage of peninsular India.