NDA Geography · World and Human Geography
Human Geography — Megacities, Population and World Places
Megacities and the three population-density measures, plus the world-places gazetteer the NDA draws on — deserts, mountains, island groups, landlocked countries and the headquarters of global organisations.
Why this matters
15 PYQs — the largest cluster in the chapter and the broadest. Two themes are conceptual: what makes a megacity (New York was the first) and the three density measures (population, physiological, agricultural). The rest is a world gazetteer of named facts — driest desert (Atacama), the Caucasus between the Caspian and Black Seas, New Zealand in Polynesia, Armenia is landlocked, the WMO is in Geneva. Drill the tables; coverage is the whole game here.
Concept 1 of 5
Megacities and population density
Intuition
A megacity is a very large urban agglomeration — by the common cut-off, a population of over 10 million. New York was the first city to reach megacity status. 'Density' is not one number but three, depending on what you divide the population by: spread it over the TOTAL area (population density), over the NET CULTIVABLE area (physiological density), or count only the FARMING population over cultivable land (agricultural density).
Definition
- Megacity — a metropolitan area with a very large population (commonly defined as over 10 million). New York was the first city to attain megacity status.
- Population density = total population ÷ total area.
- Physiological density = total population ÷ net cultivable area.
- Agricultural density = total agricultural population ÷ net cultivable area.
(All three definitions above are correct as stated in the PYQ.)
Worked example
Which density measure divides the total population by the net cultivable area (not the total area)?
Practice this conceptself-check · 4 quick reps
From the bank · past-year question
Which one of the following cities was the first to attain the status of a 'megacity'?
[Q135 · Apr · 2022]
Concept 2 of 5
World deserts and country nicknames
Intuition
The NDA returns to a small set of named deserts and country nicknames. The Atacama (in Chile/South America) is the world's DRIEST desert; the Taklamakan is a cold desert of Central Asia (in western China). Among nicknames, Denmark is called the 'country of winds' for its strong, persistent westerlies and wind-power use.
Definition
- Atacama — the world's driest desert (Chile, South America).
- Taklamakan — a cold desert of Central Asia (Xinjiang, China).
- Sahara (Africa) and Gobi (Mongolia/China) and Kalahari (southern Africa) are large but NOT the driest.
- Denmark — the 'country of winds' (strong westerlies; a wind-energy leader).
| Place | Fact |
|---|---|
| Atacama | World's driest desert (South America) NDA 2018 — Atacama is the driest desert, not the Sahara or Gobi. |
| Taklamakan | Cold desert of Central Asia (China) NDA 2017 — Taklamakan is in Central Asia. |
| Denmark | Called the 'country of winds' NDA 2020 — Denmark is the 'country of winds'. |
Practice this conceptself-check · 3 quick reps
From the bank · past-year question
Which one of the following is the driest desert of the world?
[Q78 · Apr · 2018]
Driest is not the same as biggest
The Sahara is the largest hot desert and the Gobi is huge, but the driest desert is the Atacama. Don't pick on size.
Concept 3 of 5
Rivers, mountains, oceans and island groups
Intuition
A grab-bag of physical-geography place facts the NDA likes: where a famous delta is, which mountain range separates two seas, what two oceans a canal links, which Pacific island group a country belongs to, and which city is linked to a particular activity. These are pure map memory.
Definition
- Mekong Delta — located in Vietnam (the Mekong's mouth on the South China Sea).
- Caucasus — the mountain range lying between the Caspian Sea and the Black Sea (Carpathians, Apennines and Elburz do not).
- Panama Canal — links the Atlantic Ocean and the Pacific Ocean.
- New Zealand — part of the Polynesia island group of the Pacific.
- Adelaide (Australia) — associated with viticulture (grape/wine growing).
| Place | Fact |
|---|---|
| Mekong Delta | Vietnam |
| Caucasus Mountains | Lie between the Caspian Sea and the Black Sea NDA 2020 — the Caucasus separates the Caspian and Black Seas. |
| Panama Canal | Links the Atlantic and Pacific Oceans NDA 2020 — Panama joins the Atlantic to the Pacific. |
| New Zealand | Part of Polynesia |
| Adelaide | Known for viticulture (wine) |
Practice this conceptself-check · 4 quick reps
From the bank · past-year question
Which one of the following mountains lies in between Caspian Sea and Black Sea?
[Q117 · Apr · 2020]
Concept 4 of 5
Landlocked countries
Intuition
A landlocked country has no coastline — no direct access to the sea or ocean. To pick the landlocked one from a list, ask which country is fully surrounded by other countries' land. Among Syria, Jordan, Azerbaijan and Armenia, only Armenia is landlocked (Syria has a Mediterranean coast, Jordan touches the Red Sea at Aqaba, and Azerbaijan borders the Caspian Sea — which counts as sea access in the PYQ).
Definition
- A landlocked country has no direct access to the sea or ocean — it is enclosed by land.
- Among Syria, Jordan, Azerbaijan and Armenia, only Armenia is landlocked.
- Note the borderline cases: Syria (Mediterranean coast), Jordan (Red Sea at Aqaba) and Azerbaijan (Caspian Sea coast) all have water access.
Worked example
Of Syria, Jordan, Azerbaijan and Armenia, which has NO direct access to the sea or ocean?
Practice this conceptself-check · 3 quick reps
From the bank · past-year question
Which one of the following countries does NOT have direct access to the sea/ocean?
[Q120 · Apr · 2020]
Concept 5 of 5
Global organisations and environmental conventions
Intuition
The NDA tests the seats of global organisations and the cities/years tied to environmental conventions. The World Meteorological Organization is headquartered in Geneva; the Cartagena Protocol on Biosafety (2000) takes its name from Cartagena; acid precipitation is the big environmental issue in eastern Canada; and the Biosphere Reserve idea was launched by UNESCO in 1973–74.
Definition
- World Meteorological Organization (WMO) — headquarters in Geneva, Switzerland.
- Cartagena Protocol on Biosafety (2000) — under the Convention on Biological Diversity; named after Cartagena.
- Acid precipitation (acid rain) — a major environmental issue in eastern Canada.
- Biosphere Reserves — the concept was initiated by UNESCO in 1973–74; India has many, but NOT all are in the UNESCO world network (so 'all are included' is the false statement).
| Topic | Fact |
|---|---|
| WMO headquarters | Geneva NDA 2017 — the World Meteorological Organization is in Geneva. |
| Cartagena Protocol (2000) | Biosafety, under the Convention on Biological Diversity NDA 2020 — the Biosafety Protocol is the Cartagena Protocol. |
| Eastern Canada issue | Acid precipitation |
| Biosphere Reserve idea | UNESCO, 1973–74 NDA 2020 — true: UNESCO 1973–74; false: 'all Indian reserves are in the UNESCO network'. |
Practice this conceptself-check · 4 quick reps
From the bank · past-year question
Headquarters of the World Meteorological Organization is located in
[Q69 · Apr · 2017]
'All Indian Biosphere Reserves are in the UNESCO network' is FALSE
The UNESCO 1973–74 origin is true, but the claim that every Indian Biosphere Reserve is in the UNESCO world network is false — only some are. That is the statement to reject.
Summary — formulas & gotchas at a glance
A revision cheat-sheet for the formulas and gotchas above. Click any concept name to jump back to its full explanation.
Reference tables (3)
World deserts and country nicknames3 rows
| Place | Fact |
|---|---|
| Atacama | World's driest desert (South America) NDA 2018 — Atacama is the driest desert, not the Sahara or Gobi. |
| Taklamakan | Cold desert of Central Asia (China) NDA 2017 — Taklamakan is in Central Asia. |
| Denmark | Called the 'country of winds' NDA 2020 — Denmark is the 'country of winds'. |
Rivers, mountains, oceans and island groups5 rows
| Place | Fact |
|---|---|
| Mekong Delta | Vietnam |
| Caucasus Mountains | Lie between the Caspian Sea and the Black Sea NDA 2020 — the Caucasus separates the Caspian and Black Seas. |
| Panama Canal | Links the Atlantic and Pacific Oceans NDA 2020 — Panama joins the Atlantic to the Pacific. |
| New Zealand | Part of Polynesia |
| Adelaide | Known for viticulture (wine) |
Global organisations and environmental conventions4 rows
| Topic | Fact |
|---|---|
| WMO headquarters | Geneva NDA 2017 — the World Meteorological Organization is in Geneva. |
| Cartagena Protocol (2000) | Biosafety, under the Convention on Biological Diversity NDA 2020 — the Biosafety Protocol is the Cartagena Protocol. |
| Eastern Canada issue | Acid precipitation |
| Biosphere Reserve idea | UNESCO, 1973–74 NDA 2020 — true: UNESCO 1973–74; false: 'all Indian reserves are in the UNESCO network'. |
Watch out for (2)
- Driest is not the same as biggest→ World deserts and country nicknames
- 'All Indian Biosphere Reserves are in the UNESCO network' is FALSE→ Global organisations and environmental conventions
Drill every past-year question on this subtopic
15 questions from the bank — paginated, with cart and Word-export support.