Which one of the following is the correct sequence of the given hills starting from the north and going towards the south?

1. Physiographic Divisions of the Peninsular Plateau (basic)

Welcome to our journey through the heart of India! To understand the Indian mountains, we must first master the foundation they sit upon: the Peninsular Plateau. This is not just any piece of land; it is a massive tableland composed of ancient crystalline, igneous, and metamorphic rocks. Geologically, it is one of the oldest and most stable landmasses on Earth, having formed from the breaking and drifting of the Gondwana land Contemporary India-I, Geography, Class IX, Physical Features of India, p.12. Unlike the sharp, jagged peaks of the Himalayas, this region is characterized by broad, shallow valleys and rounded hills, showing the effects of millions of years of erosion.

To make studying easier, geographers divide this vast plateau into two primary regions, separated roughly by the Narmada River. North of the Narmada lie the Central Highlands, which include the famous Malwa Plateau and are bounded by the Aravali range to the northwest and the Vindhyan range to the south Contemporary India-I, Geography, Class IX, Physical Features of India, p.12. To the south of the Narmada lies the Deccan Plateau, a triangular landmass that tilts gently from west to east. This tilt is why most major peninsular rivers, like the Godavari and Krishna, flow toward the Bay of Bengal.

Feature	Central Highlands	Deccan Plateau
Location	North of Narmada River	South of Narmada River
Key Ranges	Aravalis, Vindhyas	Satpuras, Western & Eastern Ghats
Major Plateaus	Malwa, Bundelkhand, Baghelkhand	Karnataka, Telangana, Maharashtra plateaus

Interestingly, the Peninsular Plateau doesn't stop at the mainland's edge. It extends far into the Northeast, appearing as the Meghalaya Plateau (including the Garo, Khasi, and Jaintia Hills) and the Karbi-Anglong Plateau Contemporary India-I, Geography, Class IX, Physical Features of India, p.12. These were once part of the main block but were separated by a giant geological fault (the Malda Gap). Understanding this structural unity is key to seeing India not as a collection of random hills, but as a single, interconnected geological masterpiece.

Sources: Contemporary India-I, Geography, Class IX, Physical Features of India, p.12; India Physical Environment, Geography Class XI, Structure and Physiography, p.13

2. Characteristics of Western and Eastern Ghats (basic)

The Western and Eastern Ghats constitute the structural edges of the Deccan Plateau, but they are remarkably different in their physical characteristics. The Western Ghats (locally known as the Sahyadri in Maharashtra, Nilgiris in Karnataka and Tamil Nadu, and Anaimalai and Cardamom Hills in Kerala) are a continuous chain of mountains that can only be crossed through specific passes like the Thal, Bhor, and Pal Ghats CONTEMPORARY INDIA-I, Physical Features of India, p.12. They are significantly higher than their eastern counterparts, with an average elevation of 900–1600 metres, and they play a crucial role in India's climate by causing orographic rain—forcing moisture-laden winds from the Arabian Sea to rise and shed rain on their western slopes CONTEMPORARY INDIA-I, Physical Features of India, p.12.

In contrast, the Eastern Ghats are lower, with an average elevation of about 600 metres, and stretch from the Mahanadi Valley to the Nilgiris in the south. Unlike the continuous Western range, the Eastern Ghats are discontinuous and irregular, having been heavily dissected by major rivers like the Godavari, Krishna, and Kaveri that drain into the Bay of Bengal CONTEMPORARY INDIA-I, Physical Features of India, p.12. The two ranges eventually meet at the Nilgiri Hills, which acts as a "mountain knot" Geography of India, Physiography, p.58. Interestingly, the highest peak in the entire South Indian peninsula is Anaimudi (2695 m), located in the Anaimalai Hills of the Western Ghats Geography of India, Physiography, p.58.

Feature	Western Ghats (Sahyadris)	Eastern Ghats
Continuity	Continuous; crossed only through passes.	Discontinuous; dissected by east-flowing rivers.
Elevation	Higher (900–1600 m).	Lower (Average 600 m).
Rainfall	Causes heavy orographic rain on the western side.	Receives less rainfall; parallel to the monsoon winds.
Highest Peak	Anaimudi (2695 m).	Mahendragiri (approx. 1501 m).

Sources: CONTEMPORARY INDIA-I ,Geography, Class IX . NCERT(Revised ed 2025), Physical Features of India, p.12; Geography of India ,Majid Husain, (McGrawHill 9th ed.), Physiography, p.58; INDIA PHYSICAL ENVIRONMENT, Geography Class XI (NCERT 2025 ed.), Structure and Physiography, p.12

3. Major River Systems of South India (intermediate)

The river systems of South India, also known as the Peninsular Rivers, represent some of the oldest drainage patterns in the subcontinent. Unlike the perennial Himalayan rivers, these are largely rain-fed and seasonal. The majority of these rivers, including the Godavari, Krishna, and Kaveri, originate in the Western Ghats and flow eastward into the Bay of Bengal. This eastward flow is a result of the Deccan Plateau's slight tilt from west to east NCERT Class VII, Exploring Society: India and Beyond, Chapter: Geographical Diversity of India, p.16. Among all peninsular systems, the Godavari is the most significant, often referred to as the 'Dakshin Ganga' due to its massive size and length (approx. 1500 km).

The Godavari Basin is the largest among peninsular rivers, covering roughly 10% of India's total geographical area. It rises near Nasik in Maharashtra and drains through Madhya Pradesh, Chhattisgarh, Odisha, Telangana, and Andhra Pradesh NCERT Class IX, Contemporary India-I, Chapter: Drainage, p.21. Identifying its tributaries is a favorite topic for competitive exams. Its major left-bank tributaries include the Purna, Wardha, Pranhita (the combined flow of Wardha and Wainganga), Indravati, and Sabari. Interestingly, the Manjira is its only major right-bank tributary Majid Husain, Geography of India, Chapter: The Drainage System of India, p.21.

While the Godavari leads in size, it is followed by the Krishna and Mahanadi in terms of drainage area. Below is a quick comparison of the three giants of the South:

River	Origin	Key Feature
Godavari	Trimbakeshwar (Western Ghats)	Largest Peninsular basin; vital for the National Water Grid links.
Krishna	Mahabaleshwar (Western Ghats)	Second largest eastward flowing peninsular river.
Kaveri	Brahmagiri Range (Western Ghats)	Known for its relatively consistent flow compared to other peninsular rivers.

Sources: Exploring Society: India and Beyond, Social Science-Class VII NCERT, Geographical Diversity of India, p.16; CONTEMPORARY INDIA-I, Geography, Class IX NCERT, Drainage, p.21; Geography of India, Majid Husain (McGrawHill 9th ed.), The Drainage System of India, p.21

4. Mountain Passes and Gaps in Peninsular India (intermediate)

In the context of the Peninsular Plateau, mountain passes are often referred to as 'Ghats' or 'Gaps.' Unlike the high-altitude, glaciated passes of the Himalayas, these are structural depressions or breaks in the mountain ranges that have served as vital trade and migration routes for millennia. In the Western Ghats (Sahyadris), these gaps are particularly crucial because the range is otherwise quite continuous, acting as a massive wall between the Arabian Sea coast and the Deccan interior. Moving from North to South, the most significant passes in the Western Ghats include the Thal Ghat and the Bhor Ghat in Maharashtra. The Thal Ghat (also known as Kasara Ghat) serves as the primary gateway connecting Mumbai to Nashik and eventually toward North India via National Highway 3 Majid Husain, Geography of India, Chapter 2, p.61. Just south of it lies the Bhor Ghat, which is perhaps the busiest pass in the region, linking Mumbai to Pune and facilitating massive rail and road traffic toward the southern states Majid Husain, Geography of India, Chapter 2, p.59. These passes were the engineering marvels of the 19th-century railway expansion in India. In the southern reaches of the Western Ghats, the continuity of the mountains is interrupted by much wider gaps. The Palghat Gap (or Palakkad Gap) is a 30km-wide break situated between the Nilgiri Hills to the north and the Anaimalai Hills to the south. It is the primary corridor between the state of Kerala and Tamil Nadu (specifically connecting Coimbatore to Palakkad). Further south lies the Shencottah Gap, which connects the city of Madurai in Tamil Nadu with Kollam in Kerala. Outside of the Western Ghats, the Goran Ghat in the Aravalli Range is another notable pass, providing a route between Udaipur and the regions of Sirohi and Jalore Majid Husain, Geography of India, Chapter 2, p.59.

Pass/Gap	Connecting Points	Significance
Thal Ghat	Mumbai — Nashik	Links Mumbai to the North-Eastern plateau.
Bhor Ghat	Mumbai — Pune	Links Mumbai to the Southern Deccan.
Palghat Gap	Palakkad — Coimbatore	Major break between Nilgiri and Anaimalai hills.
Goran Ghat	Udaipur — Sirohi	Located in the Aravalli Range.

Sources: Geography of India (Majid Husain), Chapter 2: Physiography, p.59, 61

5. Ecology and Biodiversity of Southern Hills (intermediate)

The southern hills of India represent a unique ecological transition where the Western Ghats and Eastern Ghats converge. This convergence happens at the Nilgiri Hills, often called the 'mountain knot.' To understand this region, one must visualize the spatial arrangement from North to South. The Nallamala Hills (Andhra Pradesh) and Javadi Hills (Tamil Nadu) are prominent sections of the Eastern Ghats, while the Nilgiris and Anaimalai Hills are part of the higher, more continuous Western Ghats system INDIA PHYSICAL ENVIRONMENT, Geography Class XI (NCERT 2025 ed.), Chapter 2, p.13. One of the most distinctive ecological features of these southern hills is the Shola forest. Found at altitudes above 1,500 meters in the Nilgiris, Anaimalai, and Palani hills, Sholas are patches of stunted tropical montane temperate forests separated by vast grasslands. Because these hills are closer to the equator, the lower reaches exhibit sub-tropical vegetation, while the higher reaches host temperate flora like Magnolia, Laurel, Cinchona, and Wattle INDIA PHYSICAL ENVIRONMENT, Geography Class XI (NCERT 2025 ed.), Natural Vegetation, p.45. These forests are incredibly rich in biodiversity, housing endemic species such as the Nilgiri Tahr and the Lion-tailed Macaque Geography of India, Majid Husain, (McGrawHill 9th ed.), Natural Vegetation and National Parks, p.49. To preserve this fragile ecosystem, the Nilgiri Biosphere Reserve was established in 1986 as India's first biosphere reserve. It covers parts of Tamil Nadu, Kerala, and Karnataka and is part of the UNESCO World Network of Biosphere Reserves Geography of India, Majid Husain, (McGrawHill 9th ed.), Natural Vegetation and National Parks, p.51. Further south, the Anaimalai hills host the Anamudi peak, the highest point in South India, highlighting the rugged and diverse terrain of this ecological hotspot.

Feature	Shola Forests	Tropical Rainforests
Location	High altitudes (Nilgiris, Anaimalai)	Lower slopes of Western Ghats
Vegetation Type	Temperate / Stunted	Dense / Lofty trees
Key Species	Magnolia, Mosses, Ferns	Ebony, Mahogany, Lianas

Sources: INDIA PHYSICAL ENVIRONMENT, Geography Class XI (NCERT 2025 ed.), Chapter 2: Structure and Physiography, p.13; INDIA PHYSICAL ENVIRONMENT, Geography Class XI (NCERT 2025 ed.), Natural Vegetation, p.45; Geography of India, Majid Husain, (McGrawHill 9th ed.), Natural Vegetation and National Parks, p.49-51; Environment, Shankar IAS Academy (ed 10th), Indian Biodiversity Diverse Landscape, p.159

6. North-South Spatial Mapping of Hill Ranges (exam-level)

To master the spatial mapping of South India's hills, we must look at the Eastern Ghats and Western Ghats as they converge toward the southern tip of the peninsula. The sequence begins in the north with the Nallamala Hills, which are located in Andhra Pradesh and Telangana, situated between the Krishna and Pennar rivers. These are part of the discontinuous Eastern Ghats chain and represent the northernmost extent when comparing major southern hill systems Geography of India, Physiography, p.62. As we move southward into Tamil Nadu, we encounter the Javadi Hills and the Shevaroy Hills. These ranges are characterized by charnockite rocks and are essential components of the Tamil Nadu Uplands, lying north of the Kaveri River Geography of India, Physiography, p.58.
The most critical geographical landmark in this mapping is the Nilgiri Hills (the 'Blue Mountains'), which serve as the mountain knot where the Eastern and Western Ghats finally meet. South of the Nilgiris, the continuity of the mountains is broken by a major tectonic feature called the Palghat Gap (or Palakkad Gap). This gap is a 25 km wide pass that connects the plains of Tamil Nadu with the coast of Kerala Geography of India, Physiography, p.58. Immediately south of this gap lie the Anaimalai Hills (home to Anamudi, the highest peak in South India), followed by the Cardamom Hills. Therefore, any North-to-South mapping must account for the transition from the Eastern Ghats (Nallamala/Javadi) to the mountain knot (Nilgiri), and finally across the Palghat Gap to the southern Western Ghats (Anaimalai).

Sources: Geography of India, Physiography, p.58; Geography of India, Physiography, p.62

7. Solving the Original PYQ (exam-level)

Having mastered the individual ranges of the Peninsular Plateau, you can now apply the concepts of merging ghats and latitudinal positioning to solve this classic spatial hierarchy question. The building blocks here are the fragmented Eastern Ghats (represented by Nallamalai and Javadi) and the southern Western Ghats (represented by Nilgiri and Anaimalai). To solve this, you must recall that the Eastern Ghats extend significantly further north into Andhra Pradesh, while the Nilgiris act as the geographical pivot point before the Western Ghats continue toward the southern tip of India.

The logical walk-through follows a clear latitudinal descent: the Nallamalai Hills (located in Andhra Pradesh/Telangana) are the northernmost in this set, followed by the Javadi Hills in northern Tamil Nadu. Moving further south, we reach the 'mountain knot' where the two ghats meet, the Nilgiri Hills. Finally, moving past the Palghat Gap into the southern section of the Western Ghats, we encounter the Anaimalai Hills. Therefore, the correct sequence is (C) Nallamalai Hills-Javadi Hills-Nilgiri Hills-Anaimalai Hills. This progression effectively maps the transition from the Eastern ranges to the high-altitude peaks of the south as detailed in INDIA PHYSICAL ENVIRONMENT, Geography Class XI (NCERT).

UPSC frequently uses relative positioning traps to confuse aspirants, particularly regarding the 'knot' region. Options (A) and (B) are common traps because they swap the Javadi and Nilgiri hills; students often forget that the Javadi Hills are part of the Eastern Ghats located north of the Nilgiri meeting point. Similarly, placing Anaimalai before Nilgiri (Option D) is a trap that ignores the Palghat Gap, which serves as a crucial marker separating the Nilgiris from the ranges further south. To avoid these traps, always visualize the Deccan Plateau's fringes as a continuous map rather than a list of isolated names.