World Regional Geography and Mapping — UPSC Geography Notes

1. The Seven Continents

Asia (about 44.6 million sq km) is the largest and most populous; Australia (about 8.6 million sq km) is the smallest and flattest.

Africa is crossed by the Equator and both Tropics; Antarctica is the highest continent on average because of its thick ice sheet.

The Ural Mountains, Ural river, Caspian Sea and Caucasus are usually taken as the Europe–Asia boundary; the Isthmus of Panama joins the Americas; the Suez isthmus separates Africa from Asia.

2. Types of Mountains

Young fold mountains (Alpine orogeny, Tertiary period): Himalaya, Alps, Andes, Rockies, Atlas, Zagros — high, rugged, seismically active.

Old fold mountains (Caledonian/Hercynian): Urals, Appalachians, Scandinavian highlands, Aravallis — worn down and rounded.

Block mountains (faulting): Vosges and Black Forest (with the Rhine rift valley between them), Sierra Nevada (USA), Satpura in India.

Volcanic mountains: Kilimanjaro, Mt Fuji, Mauna Loa and Mauna Kea, Cotopaxi, Vesuvius, Etna.

3. Major Ranges by Continent

Asia: Himalaya–Karakoram–Hindu Kush, Kunlun, Tian Shan, Altai, Zagros (Iran), Pontic and Taurus (Turkey), Western and Eastern Ghats.

Europe: Alps (Mont Blanc, 4,808 m), Pyrenees (France–Spain), Apennines (Italy), Carpathians, Dinaric Alps (Balkans), Caucasus (Elbrus, 5,642 m — Europe’s highest).

Africa: Atlas (Morocco–Algeria–Tunisia), Ethiopian Highlands, Drakensberg (South Africa), Ruwenzori (‘Mountains of the Moon’, Uganda–DR Congo).

North America: Rockies (Canada–USA), Coast Ranges, Sierra Nevada, Appalachians, Sierra Madre (Mexico); Denali (6,190 m) in Alaska.

South America: Andes — the longest continental range (about 7,000 km) through seven countries from Venezuela to Chile/Argentina; Aconcagua (6,961 m) is the highest peak outside Asia.

Australia: Great Dividing Range along the east coast. Antarctica: Transantarctic Mountains; Vinson Massif (4,892 m).

4. Highest Peaks (Seven Summits)

Everest 8,849 m (Nepal–China; height jointly announced in 2020), Aconcagua, Denali, Kilimanjaro (5,895 m, Tanzania), Elbrus, Vinson, and Kosciuszko (2,228 m, mainland Australia) or Puncak Jaya (4,884 m, New Guinea) for Oceania.

Practice

UPSC-style: Arrange from north to south — Atlas, Drakensberg, Ethiopian Highlands, Ruwenzori. (Answer: Atlas, Ethiopian Highlands, Ruwenzori, Drakensberg.)

1. Great Rivers of the World

Nile (about 6,650 km): the White Nile from the Lake Victoria region and the Blue Nile from Lake Tana (Ethiopia) meet at Khartoum; flows north to the Mediterranean. Aswan High Dam (Egypt) and the Grand Ethiopian Renaissance Dam on the Blue Nile are sources of dispute.

Amazon (about 6,400 km): rises in the Peruvian Andes, enters the Atlantic near the Equator; largest discharge and drainage basin in the world.

Yangtze (about 6,300 km): longest in Asia; Three Gorges Dam. Huang He (Yellow river) carries loess and is called ‘China’s sorrow’ for its floods.

Mississippi–Missouri: drains the USA into the Gulf of Mexico through a bird’s-foot delta.

Ob, Yenisei, Lena (Siberia) and Mackenzie (Canada) flow north into the Arctic Ocean; their mouths stay frozen while upper courses thaw, causing spring floods.

Congo crosses the Equator twice and is the deepest river; Niger has a boomerang course with an inland delta in Mali; Zambezi has Victoria Falls and the Kariba dam.

Danube flows through or along 10 countries and four capitals (Vienna, Bratislava, Budapest, Belgrade) to the Black Sea; Rhine (Alps to the North Sea at Rotterdam) is Europe’s busiest waterway; Volga is Europe’s longest and drains into the Caspian.

Mekong rises in Tibet and flows through China, Myanmar, Laos, Thailand, Cambodia and Vietnam; Tigris–Euphrates rise in Turkey and join as the Shatt al-Arab.

Murray–Darling is Australia’s main system; Paraná has the Itaipu dam (Brazil–Paraguay); Colorado carved the Grand Canyon.

2. Important Lakes

Caspian Sea — largest lake by area (salty), bordered by Russia, Kazakhstan, Turkmenistan, Iran and Azerbaijan.

Great Lakes (Superior, Michigan, Huron, Erie, Ontario — ‘HOMES’): Superior is the largest freshwater lake by area; Michigan lies wholly in the USA; Niagara Falls lies between Erie and Ontario.

Baikal (Siberia) — deepest (about 1,640 m), oldest and largest by freshwater volume.

Victoria (Uganda–Kenya–Tanzania) — largest in Africa, source region of the White Nile; Tanganyika — longest freshwater lake and second deepest; Malawi (Nyasa) — rift valley lake.

Titicaca (Peru–Bolivia) — highest navigable lake (about 3,800 m); Dead Sea (Jordan–Israel/West Bank) — lowest exposed land on Earth and hypersaline; Ladoga (Russia) — largest in Europe.

Types: tectonic/rift (Baikal, Tanganyika, Dead Sea), glacial (Great Lakes, Finnish lakes), volcanic crater/caldera (Toba in Sumatra), oxbow, lagoon, and man-made reservoirs (Lake Volta, Ghana, is among the largest by area).

Practice

UPSC-style: Which of these rivers flows into the Arctic Ocean — Amur, Lena, Mekong, Volga? (Answer: Lena.)

1. Key Chokepoints

Strait of Hormuz: between Iran and Oman (Musandam); links the Persian Gulf with the Gulf of Oman and Arabian Sea — the most important oil chokepoint; India imports much of its crude and LNG through it.

Strait of Malacca: between the Malay Peninsula and Sumatra; links the Andaman Sea (Indian Ocean) with the South China Sea; the shortest sea route between the Indian Ocean and East Asia, narrowest near Singapore. China’s dependence on it is called the ‘Malacca dilemma’.

Bab-el-Mandeb: between Yemen and Djibouti/Eritrea; links the Red Sea with the Gulf of Aden — the southern gate to the Suez route.

Suez Canal (Egypt): opened 1869, about 193 km, sea-level canal without locks, Port Said (Mediterranean) to Suez (Red Sea); nationalised in 1956; a parallel channel was added in 2015.

Panama Canal: opened 1914, about 82 km, a lock canal that lifts ships to Gatun Lake; joins the Atlantic (Caribbean) and Pacific; handed over to Panama in 1999; larger locks opened in 2016. It depends on rain-fed lake water, so droughts limit traffic.

Turkish Straits: Bosphorus (through Istanbul; Black Sea–Sea of Marmara) and Dardanelles (Marmara–Aegean) — the only sea link of Russia’s and Ukraine’s Black Sea ports; passage governed by the Montreux Convention (1936).

Strait of Gibraltar: between Spain and Morocco; Atlantic–Mediterranean.

2. Other Important Straits

Dover (England–France, narrowest part of the English Channel), Bering (Russia–USA; Pacific–Arctic, crossed by the International Date Line), Palk (India–Sri Lanka), Sunda (Java–Sumatra) and Lombok (Bali–Lombok, deep alternative to Malacca), Taiwan Strait, Korea (Tsushima) Strait, Magellan (mainland South America–Tierra del Fuego), Drake Passage (South America–Antarctica), Mozambique Channel, Otranto (Italy–Albania), Messina (Italy–Sicily), Bass (Australia–Tasmania), Cook (North–South Islands, New Zealand), Florida (USA–Cuba), Hudson and Davis (Canada–Greenland).

3. Other Ship Canals

Kiel Canal (Germany; North Sea–Baltic, among the busiest artificial waterways), St Lawrence Seaway and Welland Canal (Great Lakes–Atlantic, bypassing Niagara Falls), Soo Locks (Superior–Huron), Corinth Canal (Greece), Volga–Don Canal (Russia), Grand Canal (China, the oldest and longest canal system).

4. Why Chokepoints Matter

Blockades, piracy, conflict or accidents (such as the 2021 grounding of the Ever Given in the Suez Canal) can halt global trade and raise freight and insurance costs.

Alternatives are long and costly: rerouting around the Cape of Good Hope adds thousands of nautical miles to Asia–Europe voyages.

India’s location near Hormuz, Bab-el-Mandeb and Malacca (with the Andaman & Nicobar Islands overlooking the Six/Ten Degree Channels) gives it strategic weight in the Indian Ocean.

Practice

UPSC-style: Which of the following pairs is correctly matched — Bab-el-Mandeb : Red Sea–Gulf of Aden; Bosphorus : Aegean–Mediterranean; Hormuz : Red Sea–Arabian Sea? (Answer: only the first.)

1. West Asia

Persian Gulf (8): Iran, Iraq, Kuwait, Saudi Arabia, Bahrain, Qatar, UAE, Oman.

Red Sea: Egypt, Sudan, Eritrea, Djibouti on the African side; Saudi Arabia and Yemen on the Arabian side; Israel and Jordan reach it through the Gulf of Aqaba.

Gulf of Aden: Yemen, Djibouti, Somalia. Gulf of Oman: Oman, UAE, Iran (with Pakistan at its eastern edge).

Dead Sea (an inland salt lake): Jordan, Israel and the West Bank.

2. Europe and Central Asia

Black Sea (6): Turkey, Bulgaria, Romania, Ukraine, Russia, Georgia.

Caspian Sea (5): Russia, Kazakhstan, Turkmenistan, Iran, Azerbaijan; its legal status was settled by the Aktau Convention (2018).

Baltic Sea (9): Sweden, Finland, Russia, Estonia, Latvia, Lithuania, Poland, Germany, Denmark. Its arms include the Gulfs of Bothnia, Finland and Riga.

North Sea: UK, Norway, Denmark, Germany, Netherlands, Belgium, France.

Adriatic Sea: Italy, Slovenia, Croatia, Bosnia and Herzegovina (short coast at Neum), Montenegro, Albania. Aegean Sea: Greece and Turkey.

Mediterranean Sea: about 20 countries across three continents — from Spain, France, Italy, Greece and Turkey to Syria, Lebanon, Israel, Egypt, Libya, Tunisia, Algeria and Morocco, plus island states Malta and Cyprus.

Aral Sea (a shrinking lake): Kazakhstan and Uzbekistan.

3. Asia-Pacific

South China Sea: China, Taiwan, Philippines, Malaysia, Brunei, Indonesia, Vietnam — overlapping claims over the Spratly and Paracel islands; the 2016 arbitral award under UNCLOS rejected China’s ‘nine-dash line’.

East China Sea: China, Taiwan, Japan, South Korea (Senkaku/Diaoyu dispute). Yellow Sea: China, North Korea, South Korea. Sea of Japan (East Sea): Japan, Russia, North Korea, South Korea.

Andaman Sea: Myanmar, Thailand, Malaysia, Indonesia, India (Andaman & Nicobar Islands). Arabian Sea: India, Pakistan, Iran, Oman, Yemen, Somalia; also the Maldives.

4. Americas and Africa

Gulf of Mexico: USA, Mexico, Cuba. Caribbean Sea: Central American and South American states (Mexico to Venezuela) and the Caribbean islands.

Gulf of Guinea: West and Central African coast (roughly Liberia to Gabon, including Ghana, Nigeria, Cameroon) — a piracy hotspot.

Sargasso Sea (North Atlantic) has no land coast; it is bounded by ocean currents.

Practice

UPSC-style: Which of these countries does NOT border the Black Sea — Bulgaria, Georgia, Moldova, Romania? (Answer: Moldova.)

1. Why Deserts Form

Subtropical high pressure: descending, warming air of the Hadley cell gives clear skies (Sahara, Arabian, Australian deserts).

Cold currents: cool the air from below and make it stable, so coastal deserts get fog but little rain — Atacama (Peru/Humboldt current), Namib (Benguela), Baja California (California current), western Australia (West Australian current).

Rain-shadow: mountains block moist winds — Patagonia (Andes), Great Basin (Sierra Nevada), Ladakh (Himalaya).

Continentality: distance from the sea — Gobi, Taklamakan, Karakum, Kyzylkum.

2. Major Hot Deserts

Sahara (North Africa) — largest hot desert (about 9 million sq km); Arabian — includes the Rub’ al Khali (‘Empty Quarter’), the largest continuous sand sea.

Kalahari (Botswana, Namibia, South Africa) — semi-arid, home of San people; Namib — coastal fog desert of Namibia.

Atacama (Chile) — driest non-polar desert, rich in copper, nitrates and lithium.

Great Australian deserts: Great Victoria (largest in Australia), Great Sandy, Gibson, Simpson.

North America: Sonoran, Mojave (Death Valley) and Chihuahuan; South Asia: Thar (India–Pakistan).

3. Mid-latitude (Cold) Deserts

Gobi (Mongolia–China), Taklamakan (Tarim basin, Xinjiang), Karakum (Turkmenistan), Kyzylkum (Uzbekistan–Kazakhstan), Patagonian (Argentina), Great Basin (USA). Antarctica is the largest desert of all (a polar desert).

4. Tropical Grasslands

Savanna (East and Central Africa — Serengeti), Llanos (Orinoco basin, Venezuela–Colombia), Campos (Brazilian Highlands), and the northern Australian savanna: tall grass with scattered trees, wet summer and dry winter.

5. Temperate Grasslands

Prairies (North America), Pampas (Argentina), Steppes (Ukraine to Central Asia), Veld (South Africa), Downs (Murray–Darling basin, Australia), Canterbury plains (New Zealand), Puszta (Hungary), Manchurian grasslands (China). Short grass, few trees, cold winters — today the world’s great wheat and livestock belts.

6. Desertification

Land degradation in drylands from over-grazing, deforestation, poor irrigation (salinisation) and climate change. The UN Convention to Combat Desertification (UNCCD, 1994) leads global action; 17 June is Desertification and Drought Day; Africa’s Great Green Wall (launched 2007) aims to restore land across the Sahel.

Practice

UPSC-style: Why are the world’s major hot deserts located on the western margins of continents? Explain with examples.

1. Types of Islands

Continental islands: parts of the continental shelf separated by rising sea level or rifting — Great Britain, Sri Lanka, Tasmania, Madagascar, and the granitic Seychelles.

Volcanic (oceanic) islands: built by hotspots or plate boundaries — Hawaii (hotspot), Iceland and the Azores (on the Mid-Atlantic Ridge), Canary Islands, Galápagos.

Island arcs: curved chains at subduction zones — Japan, the Philippines, the Aleutians, Indonesia.

Coral islands and atolls: built by reef-building corals in warm, clear, shallow seas — Maldives, Lakshadweep, many Pacific islands.

2. Largest Islands

Greenland (Denmark, self-governing) > New Guinea (Papua New Guinea and Indonesia) > Borneo (Indonesia, Malaysia, Brunei — the only island shared by three countries) > Madagascar > Baffin (Canada) > Sumatra > Honshu (Japan) > Great Britain.

Australia is treated as a continent, not an island.

3. Island Countries and Groups

Indonesia (over 17,000 islands — largest archipelagic state), Philippines (over 7,000), Japan (four main islands: Hokkaido, Honshu, Shikoku, Kyushu), Maldives (about 1,190 coral islands in 26 atolls), New Zealand (North and South Islands separated by Cook Strait).

Indian Ocean: Sri Lanka, Madagascar, Mauritius and Réunion (France) — the Mascarenes, Seychelles, Comoros and Mayotte (France), Zanzibar (Tanzania), Socotra (Yemen), and India’s Andaman & Nicobar and Lakshadweep groups.

Atlantic: Azores and Madeira (Portugal), Canary Islands (Spain), Cape Verde, Iceland, the Caribbean’s Greater and Lesser Antilles, and the Falklands.

Mediterranean: Sicily (largest), Sardinia (Italy), Corsica (France), Crete (Greece), Cyprus, Malta. Arctic: Svalbard (Norway), Novaya Zemlya (Russia), Canadian Arctic Archipelago.

4. Disputed and Strategic Islands

Spratly and Paracel Islands (South China Sea) — claimed in whole or part by China, Taiwan, Vietnam, the Philippines, Malaysia and Brunei.

Senkaku/Diaoyu (Japan–China, East China Sea); Kuril Islands (Russia–Japan, occupied by the USSR in 1945); Falklands/Malvinas (UK–Argentina, 1982 war).

Chagos Archipelago (Diego Garcia base) — UK–Mauritius sovereignty dispute; the ICJ’s 2019 advisory opinion said the UK should end its administration.

Hawaii, Guam and Diego Garcia host major military bases; India is developing infrastructure in the Andaman & Nicobar Islands for its Indian Ocean role.

Practice

UPSC-style: Which island is shared by three countries — Borneo, New Guinea, Timor, Hispaniola? (Answer: Borneo.)

1. Aral Sea (Kazakhstan–Uzbekistan)

Once among the four largest lakes in the world, it began shrinking in the 1960s when Soviet planners diverted the Amu Darya and Syr Darya rivers to irrigate cotton.

It split into a North (Small) Aral and a South (Large) Aral; much of the South Aral’s eastern basin has dried up, leaving the salty, dusty Aralkum desert.

Impacts: collapse of fisheries (stranded ports such as Moynaq), toxic dust storms, respiratory illness and a harsher local climate. The Kok-Aral dam (2005, Kazakhstan) has partly revived the North Aral.

2. Lake Chad (Chad, Cameroon, Niger, Nigeria)

A shallow Sahelian lake that has lost about 90% of its area since the 1960s due to drought, rainfall variability, irrigation and population pressure.

Shrinkage has hurt fishing, farming and herding and is linked with displacement and insecurity in the basin; an inter-basin transfer from the Congo basin (‘Transaqua’) has been proposed.

3. Dead Sea (Jordan–Israel/West Bank)

Its level has been falling by around a metre a year because the Jordan river’s water is diverted and the sea is used for mineral evaporation ponds; sinkholes have opened along its shores. A Red Sea–Dead Sea water conveyance has been proposed.

Other shrinking lakes: Lake Urmia (Iran), Lake Poopó (Bolivia, largely dried by 2015–16) and the Great Salt Lake (USA, record low in 2022).

4. Arctic Sea Ice

Satellite records since 1979 show the September minimum extent declining by roughly 12–13% per decade (NASA); the record low was in 2012.

IPCC AR6 (2021): the Arctic is likely to be practically ice-free in September at least once before 2050 under all emission scenarios.

Feedback: loss of reflective ice lowers albedo, so the Arctic warms several times faster than the global average (Arctic amplification). New shipping routes (Northern Sea Route) and resource competition follow.

5. Permafrost

Ground frozen for at least two consecutive years, covering roughly a quarter of the Northern Hemisphere’s land (Siberia, Alaska, Canada, Tibetan Plateau).

It stores about twice as much carbon as the atmosphere; thawing releases CO₂ and methane (a positive feedback), creates thermokarst and craters (Batagaika, Siberia), and damages pipelines, roads and buildings.

6. Himalayan Glaciers (the ‘Third Pole’)

ICIMOD’s Hindu Kush Himalaya Assessment (2019) found that even if warming is limited to 1.5°C, about one-third of the region’s glaciers would be lost by 2100, and two-thirds if emissions stay high.

Impacts: more glacial lakes and GLOF risk, an initial rise and later fall in river flows (‘peak water’) for the Indus, Ganga and Brahmaputra, and stress on hydropower and irrigation.

Practice

UPSC-style: ‘The shrinking of the Aral Sea is a man-made disaster with lessons for India.’ Discuss with reference to water management.

1. Factors of Industrial Location

Raw materials, power, labour, market, transport, capital, water, government policy and agglomeration economies (shared suppliers, skills and services).

Over time, transport improvements and technology have reduced the pull of raw materials and increased the pull of markets, skills and policy incentives.

2. Weber’s Least-Cost Theory (1909)

Assumptions: an isolated, uniform region; fixed locations of raw materials and market; transport cost proportional to weight and distance; fixed labour locations; perfect competition.

Raw materials: ubiquitous (available everywhere, e.g. water) or localised; localised ones are pure (whole weight enters the product, e.g. cotton) or gross (weight-losing, e.g. iron ore, coal, sugarcane).

Material Index = weight of localised raw materials ÷ weight of product. If it is more than 1 (weight-losing), industry locates near raw materials (iron and steel, sugar, cement); if less than 1 (weight-gaining, using ubiquitous inputs), it locates near the market (bottling of soft drinks, bakeries).

Locational triangle: with two raw-material sources and one market, the least-transport-cost point lies within the triangle.

Labour and agglomeration: an industry may move away from the least-transport-cost point if savings on cheap labour or from clustering exceed the extra transport cost; lines of equal extra cost are called isodapanes.

Criticism: unrealistic assumptions, neglect of demand and profit, and of tapering transport rates; later thinkers — August Lösch (profit-maximising market areas), Edgar Hoover (terminal and transfer costs) and David Smith (spatial margins of profitability) — refined the idea.

3. Footloose Industries

Industries not tied to a particular raw material or location — electronics, software, diamond cutting, watches, high-value pharmaceuticals.

They depend on skilled labour, connectivity, research institutions, capital and quality of life; generally clean and high-value.

Examples: Silicon Valley (California), Bengaluru and Hyderabad (India), Hsinchu (Taiwan), Shenzhen (China).

4. Major Industrial Regions of the World

USA: the North-Eastern/Great Lakes manufacturing belt — Pittsburgh (iron and steel), Detroit (automobiles), Chicago; the Sun Belt and California for high-tech.

Europe: the Ruhr (Germany) grew on coal and steel and has restructured towards services and technology; the English Midlands and Lancashire (Manchester textiles); northern Italy.

Japan: the Pacific belt — Keihin (Tokyo–Yokohama), Hanshin (Osaka–Kobe; Osaka is the ‘Manchester of Japan’), Chukyo (Nagoya; Toyota) and Kitakyushu — built on imported raw materials and coastal sites.

China: Pearl River Delta (Guangzhou–Shenzhen–Hong Kong), Yangtze River Delta (Shanghai) and the Bohai Rim (Beijing–Tianjin) — export-oriented manufacturing hubs.

Russia: Central (Moscow) region, the Urals (Magnitogorsk) and the Kuznetsk Basin (Kuzbass coal). South Korea: Ulsan (shipbuilding, automobiles).

Practice

UPSC-style: ‘Weight-losing raw materials pull industries to their source.’ Explain using Weber’s theory with examples of the iron and steel and sugar industries.