Mountain Passes & Channels: Zoji La, Nathu La, Ten Degree
November 4, 20267 min read
You see "Zoji La" and remember Ladakh. You see "Nathu La" and remember Sikkim. You see "Ten Degree Channel" and remember Andaman and Nicobar.
Those instincts are correct. What UPSC tests is the second layer: which range, which side of the border, which pair of islands, and which pass has been made obsolete by a tunnel.
This note covers the three names that appear in options together — Zoji La, Nathu La and the Ten Degree Channel — and the neighbouring facts that turn each one into a trap.
[TOPIC CLASSIFICATION]
Topic type: Geography — Himalayan passes and maritime channels
PYQ frequency: High. Channels were asked directly in 2014; passes keep appearing through river-origin and map questions.
Exam stage relevance: Prelims primary; useful in Mains for border infrastructure and connectivity.
Primary GS Paper: GS 1 (Geography); GS 3 (Infrastructure and Security)
[EXAMINER REASONING]
Trap: "Zoji La is the highest pass on the Srinagar–Leh highway." FALSE. Fotu La at 4,108 m is the highest point on NH-1. Zoji La is about 3,528 m.
Most confused: Nathu La and Jelep La — both in Sikkim, both on old Tibet trade routes, only about 3 km apart as the crow flies. Also the 8, 9 and 10 degree channels.
Key anchor: Zoji La links Kashmir with Ladakh. Nathu La links Sikkim with Tibet. The Ten Degree Channel separates Little Andaman from Car Nicobar.
Current affairs hook: The Zojila Tunnel achieved breakthrough on 9 June 2026 but is not open yet. Nathu La and Shipki La border trade resumed on 1 August 2026 after a six-year suspension.
Mains hinge: All-weather connectivity in fragile Himalayan terrain — the strategic gain, the ecological cost and the disaster risk have to be weighed together, not listed separately.
The 3 Traps
Trap 1: Zoji La is the highest pass on the Srinagar–Leh highway
You remember Zoji La because it is the dramatic one. It is the gateway from the Kashmir Valley into Ladakh, it closes under snow every winter, and it was the scene of Operation Bison in 1948, when Indian forces moved tanks to an altitude no tank had reached before.
None of that makes it the highest pass on the route.
Zoji La: about 3,528 m. Lies at the edge of the Great Himalaya and the Zanskar Range, between Sonamarg and Drass.
Fotu La: 4,108 m, in the Zanskar Range. This is the highest point on the Srinagar–Leh highway.
In fact, Zoji La is the lowest drivable pass across the Great Himalaya. That is exactly why the highway uses it.
Do not attach Zoji La to the Pir Panjal. The Pir Panjal is Rohtang and Atal Tunnel country, on the Manali side.
Numbers worth locking: Zoji La 3,528 m; Fotu La 4,108 m; Khardung La about 5,359 m; Umling La 5,798 m, the world's highest motorable road, built by the Border Roads Organisation under Project HIMANK on the Chisumle–Demchok route.
Trap 2: Nathu La and Jelep La are interchangeable
Both are in Sikkim. Both cross into Tibet's Chumbi Valley. Both carry Silk Route history. They are not the same pass.
Nathu La: on the Dongkya Range, about 4,310 m, roughly 52 km east of Gangtok. It was sealed after the 1962 war and reopened for trade on 6 July 2006. Trade was suspended again in 2020 and resumed on 1 August 2026.
Jelep La: roughly 4,300 m, served the Kalimpong route, and sits about 3 km from Nathu La as the crow flies. It remained closed after 1962 and has not reopened.
Two statements UPSC can build from this: "Nathu La is in Arunachal Pradesh" is false. "Nathu La connects Sikkim with Nepal" is false. It connects Sikkim with the Tibet Autonomous Region of China.
Do not confuse Nathu La with Shipki La. Shipki La is in Kinnaur district, Himachal Pradesh, and it is the pass through which the Sutlej enters India from Tibet. Border trade at Shipki La also resumed on 1 August 2026.
Trap 3: The degree channels
The channels are named for the latitude they sit on, and they are easy to shuffle under exam pressure.
Ten Degree Channel (about 10 degrees north): separates the Andaman Islands from the Nicobar Islands. More precisely, Little Andaman from Car Nicobar. About 150 km wide.
Nine Degree Channel (about 9 degrees north): separates Minicoy from the main Lakshadweep group. About 200 km wide, and it carries most merchant shipping between Europe and East Asia.
Eight Degree Channel (about 8 degrees north): separates Minicoy from the Maldives. The India–Maldives maritime boundary runs through it.
Mnemonic: 10 splits the island groups, 9 splits Lakshadweep, 8 splits India from the Maldives.
The Ten Degree Channel does not separate India from Sri Lanka. The Palk Strait and the Gulf of Mannar do.
Three more separations that appear in the same options: the Duncan Passage separates South Andaman from Little Andaman; the Grand Channel separates Great Nicobar from Sumatra; the Coco Channel separates the Andamans from Myanmar's Coco Islands.
Core Concept
A pass is a low point in a mountain ridge that allows movement across it. A channel is a narrow body of water between two land masses.
In the Himalayas, passes matter because they are the only feasible road routes through the mountains — which is why connectivity projects are strategic, not just infrastructural. In the islands, channels define maritime boundaries, shipping lanes and administrative separation.
The same logic runs through the Western Ghats. The Palghat Gap, about 30 km wide between the Nilgiri and Anaimalai hills, is the main road and rail corridor between Kerala and Tamil Nadu. The Thal Ghat and Bhor Ghat play the same role for Mumbai's links to Nashik and Pune.
Key Facts
Pass or Channel
Location
Range or water body
What it connects
Exam point
Zoji La
J&K–Ladakh
Great Himalaya edge, Zanskar Range
Srinagar to Kargil and Leh via Sonamarg, Drass
About 3,528 m; winter closure; Zojila Tunnel under it
Fotu La
Ladakh
Zanskar Range
Srinagar–Leh highway
4,108 m; highest point on NH-1
Khardung La
Ladakh
Ladakh Range
Leh to Nubra Valley
About 5,359 m; older "highest motorable" claim
Umling La
Ladakh
Ladakh Range
Chisumle to Demchok
5,798 m; world's highest motorable road
Nathu La
Sikkim
Dongkya Range
Sikkim to Tibet's Chumbi Valley
About 4,310 m; reopened 2006; trade resumed August 2026
Which pair of islands does the Ten Degree Channel separate? Answer: Andaman and Nicobar
2021
Prelims
Which river joins the Indus directly? Answer: the Sutlej, which enters India through Shipki La
2010
Prelims
Which rivers pass through Himachal Pradesh? The Satluj enters the state at Shipki La
2009
Prelims
Which river does not originate in India? The Sutlej, which rises near Rakshastal in Tibet
Pass–state pairing is a standard Prelims format. Learn these as fixed pairs: Nathu La–Sikkim, Shipki La–Himachal Pradesh, Lipulekh–Uttarakhand, Rohtang–Himachal Pradesh, Bomdi La–Arunachal Pradesh.
Statement Elimination Guide
Correct: "Zoji La connects the Kashmir Valley with Ladakh on the Srinagar–Leh highway."
False: "Zoji La is the highest pass on the Srinagar–Leh highway." (Fotu La, at 4,108 m, is higher. Zoji La is about 3,528 m.)
Trap: "Zoji La lies in the Pir Panjal Range." (It lies at the Great Himalaya edge, near the Zanskar Range. Pir Panjal is the Rohtang side.)
Correct: "Nathu La is in Sikkim and connects India with the Tibet Autonomous Region."
False: "Nathu La connects Sikkim with Nepal." (It connects Sikkim with Tibet. Nepal is further west.)
Trap: "Jelep La and Nathu La are the same pass." (They are distinct, both in Sikkim, about 3 km apart as the crow flies. Jelep La has stayed closed since 1962.)
Correct: "The Ten Degree Channel separates the Andaman Islands from the Nicobar Islands."
False: "The Ten Degree Channel separates India from Sri Lanka." (That is the Palk Strait and Gulf of Mannar.)
Trap: "The Nine Degree Channel separates the Andamans from the Nicobars." (It separates Minicoy from the main Lakshadweep group.)
Correct: "The Sutlej enters India through Shipki La in Himachal Pradesh."
False: "Shipki La is in Sikkim." (It is in Kinnaur district, Himachal Pradesh.)
Current Affairs Hook
Zojila Tunnel: 13.153 km, single-tube, two-lane, bi-directional, on the Srinagar–Kargil–Leh axis. Final breakthrough came on 9 June 2026, about six months ahead of schedule. Breakthrough is not completion. Civil works, ventilation, lighting and finishing remain, and official estimates point to an opening around early 2028. Once open, it will cut the Sonamarg–Minimarg crossing from roughly 1.5 to 2 hours to about 15 to 30 minutes and keep the route open through winter.
Nathu La and Shipki La trade: Border trade at both passes resumed on 1 August 2026 after a suspension since 2020. The trade is seasonal, roughly May to November, and limited to a notified list of commodities. Nathu La had first reopened in 2006 after 44 years.
Fotu La tunnel: A twin-tube tunnel at Fotu La has been approved at about Rs 1,196 crore, with a 1.96 km tunnel and 0.69 km of approach roads. It is the next step in making the Srinagar–Leh corridor all-weather beyond Zojila.
Interlinkages
India–China relations (GS 2): Nathu La and Shipki La trade are small in value but large in symbolism. They sit alongside the Sikkim status question and the 1962 war legacy.
Internal security and border infrastructure (GS 3): all-weather access to Ladakh is a defence logistics question first and a tourism question second.
Environment and disaster management (GS 3): tunnelling in Himalayan terrain raises slope stability, drainage, debris disposal, biodiversity and glacial-lake outburst risk. The Zojila and Fotu La projects belong in answers on disaster-resilient infrastructure.
Geography of the islands (GS 1): the degree channels connect to maritime boundaries, the Andaman–Nicobar administrative split, and the strategic value of the Nine Degree Channel shipping lane.
For the project details, see the dedicated note on Zojila Tunnel.
Common Mistakes
"Zoji La is the highest pass on the Srinagar–Leh highway." It is not. Fotu La at 4,108 m is the highest point. Zoji La is about 3,528 m and is the lowest drivable pass across the Great Himalaya.
"Nathu La and Jelep La are the same pass." They are separate passes in Sikkim. Nathu La reopened in 2006 and saw trade resume in August 2026. Jelep La has stayed closed since 1962.
"The Ten Degree Channel separates India from Sri Lanka." It separates the Andaman group from the Nicobar group. The Palk Strait and Gulf of Mannar separate India from Sri Lanka.
"The Zojila Tunnel is open." Breakthrough happened in June 2026. Opening is expected around early 2028.
"Shipki La is in Sikkim." It is in Kinnaur, Himachal Pradesh, and it is where the Sutlej enters India.
Revision Snapshot
Zoji La about 3,528 m, Great Himalaya edge, Srinagar–Leh; Fotu La 4,108 m, highest on NH-1. Nathu La about 4,310 m, Sikkim to Tibet, reopened 2006, trade resumed August 2026; Jelep La still closed; Shipki La in Himachal, Sutlej entrance, trade resumed August 2026. Channels: 10 splits Andaman from Nicobar (Little Andaman–Car Nicobar), 9 splits Minicoy from main Lakshadweep, 8 splits Minicoy from the Maldives. Duncan Passage splits South Andaman from Little Andaman. Zojila Tunnel 13.153 km, breakthrough June 2026, opening expected around 2028.