Palghat Gap

Also called: Palakkad Gap · Topic: Structure and Physiography of India: Himalayas, Plains, Peninsula, Coasts and Islands · NCERT: Beyond NCERT

Meaning

The Palghat Gap (also called the Palakkad Gap) is a low break in the Western Ghats, 30–40 km wide, that lies between the Nilgiri hills to the north and the Anaimalai hills to the south, and links Kerala with Tamil Nadu. It matters because it is one of the few easy ways across the high, unbroken Western Ghats. Roads, railways and the moist south-west monsoon winds all pass through it.

Explanation

What a gap is and why the Western Ghats need one

• Pass / gap: a low break in a mountain chain. Roads, railways, rivers or winds can cross the chain through it.
• The Western Ghats are a wall:
• They form a long, continuous chain, about 1,600 km long, along the western edge of the Peninsula [1].
• Their average height is about 1,500 m, and they get higher from north to south.

• They rise as a steep escarpment (a steep, cliff-like slope) of about 1,000 m or more above the coast [3].

• Result: the west coast is cut off from the inner plateau. Crossing points are few, so each one becomes very important.

• In the far south, where the hills are highest, the Palghat Gap is the widest and lowest crossing.

Its position: between two high blocks

• North side — Nilgiri hills:
• This is the high block where the Western Ghats and the Eastern Ghats meet.

• Dodabetta (2,637 m), the second highest peak of the Peninsula, lies here, near Ooty, Tamil Nadu.

• South side — Anaimalai hills:

• These hills lie on the Kerala–Tamil Nadu border.

• Anamudi (2,695 m), the highest peak of the Peninsula, lies here, in Idukki district, Kerala.

• The gap itself: a wide, low corridor between these two high blocks. Its western end is at Palakkad (Kerala) and its eastern end opens towards Coimbatore (Tamil Nadu).

• So the Palghat Gap separates the two highest blocks of the southern Western Ghats.

How it lets the monsoon through

• Normal case — rain shadow (the dry side of a mountain, away from the wind):
• The moist south-west monsoon blows in from the Arabian Sea and hits the Western Ghats.
• The air is pushed up. Rising air cools, its water vapour condenses, and heavy rain falls on the windward (wind-facing) slope: 250–400 cm.

• The air comes down the eastern side. Sinking air warms up and keeps the moisture it has left, so the land east of the Ghats stays dry.

• What the gap changes:

• At the gap there is no high wall to force the wind up.
• So some moist south-west monsoon wind flows straight through to the east.
• Result: Coimbatore gets some rain even though it lies east of the Ghats. Places behind the unbroken parts of the Ghats get much less.

How it shapes movement and trade

• Road and rail corridor: the gap carries the main road and rail links between Kerala and Tamil Nadu (Palakkad–Coimbatore).
• Wider route: it forms part of the Kochi–Coimbatore corridor, which joins the Kerala coast with the interior of Tamil Nadu.
• Low and wide: routes can cross here without the steep climbs needed at passes such as Bhor Ghat or Thal Ghat in the Sahyadri.

Where it occurs

• Location: the southern Western Ghats, on the Kerala–Tamil Nadu border.
• North: Nilgiri hills (where Tamil Nadu, Karnataka and Kerala join).

• South: Anaimalai hills (Kerala–Tamil Nadu).

• Towns at each end: Palakkad (Kerala) on the west side and Coimbatore (Tamil Nadu) on the east side.

• Place among the Western Ghats crossings (north to south):
• Thal Ghat (Kasara Ghat): Mumbai–Nashik, northern Sahyadri.
• Bhor Ghat (Khandala Ghat): Mumbai–Pune, Sahyadri.
• Palghat Gap: Palakkad–Coimbatore, between the Nilgiris and the Anaimalai.

• Shencottah Gap: between the Cardamom and Agasthyamalai hills, linking Kollam (Kerala) with the Tirunelveli side (Tamil Nadu).

• Order of the local hill names around it (north to south): Sahyadri → Nilgiri → [Palghat Gap] → Anaimalai → Cardamom → [Shencottah Gap] → Agasthyamalai.

Don't confuse with

• Shencottah Gap: this lies further south, between the Cardamom and Agasthyamalai hills, and links Kollam with the Tirunelveli side. The Palghat Gap lies between the Nilgiris and the Anaimalai.
• Bhor Ghat / Thal Ghat: these are passes in the northern Sahyadri (Maharashtra). Bhor Ghat carries Mumbai–Pune and Thal Ghat carries Mumbai–Nashik. The Palghat Gap is a wide, low gap in the far south (Kerala–Tamil Nadu).
• Nilgiri hills (junction): the Nilgiris are where the Western and Eastern Ghats meet. They are a high block, not a break. The Palghat Gap is the low break just south of them.
• Rain shadow area: inner places such as Pune, Marathwada and interior Karnataka stay dry behind an unbroken Ghat wall. Coimbatore gets some monsoon rain because the gap lets the wind through.

Prelims Hooks

• Palghat Gap lies between the Nilgiri hills (north) and the Anaimalai hills (south). It is 30–40 km wide.
• It links: Kerala and Tamil Nadu, from Palakkad to Coimbatore, by road and rail.
• Climate effect: the south-west monsoon passes through the gap, so Coimbatore gets some rain even though it lies east of the Ghats.
• Order of crossings (north to south): Thal Ghat → Bhor Ghat → Palghat Gap → Shencottah Gap.
• Trap: the hills on either side hold the Peninsula's two highest peaks. Dodabetta (2,637 m) is in the Nilgiris, to the north. Anamudi (2,695 m) is in the Anaimalai, to the south. Neither peak is in the gap.
• Trap: a question may say the Palghat Gap lies between the Cardamom and Agasthyamalai hills. That is the Shencottah Gap.

Mains Points

• Relief and connectivity: the Western Ghats form a continuous wall, and the Palghat Gap is the main low break in the south.
• It carries the Kochi–Coimbatore road and rail corridor.
• This joins Kerala's ports and coast with the interior of Tamil Nadu and helps trade between the two states.

• The northern passes (Thal and Bhor) do the same job for Mumbai (GS-I, GS-III infrastructure).

• Relief and rainfall: the gap breaks the usual rain-shadow pattern.

• Moist south-west monsoon winds reach Coimbatore. This helps its farming and textile base.
• Inner areas behind the unbroken Ghats, such as Marathwada and north interior Karnataka, stay drought-prone.

• This is a clear example of how landforms control the regional spread of rain and water.

• Conservation in a corridor zone: the gap lies between two very rich hill blocks of a UNESCO World Heritage Site (2012) and biodiversity hotspot. The Nilgiris hold India's first biosphere reserve (1986), and the Anaimalai hold Eravikulam National Park. Busy transport corridors through such areas need to be planned with the eco-sensitive area debate in mind. The Gadgil report treated the whole Ghats as sensitive, and the Kasturirangan report proposed about 37% as ESA [2].

Related concepts

• Deccan Plateau
• Western Ghats
• Eastern Ghats
• Anamudi
• Dodabetta
• Nilgiri hills
• Thal Ghat and Bhor Ghat
• Nallamala hills

Read more

• The Deccan Plateau and the Western and Eastern Ghats