Question map
Consider the following pairs : River Flows into The 1. Mekong - Andaman Sea 2. Thames - Irish Sea 3. Volga - Caspian Sea 4. Zambezi - Indian Ocean Which of the pairs given above is/are correctly matched ?
Explanation
The correct answer is Option 3 (3 and 4 only). This is determined by the geographical drainage patterns of the major rivers mentioned.
- Pair 3 is correct: The Volga is Europe's longest river. It flows through Central Russia and drains into the Caspian Sea, forming a large delta.
- Pair 4 is correct: The Zambezi is the largest river flowing into the Indian Ocean from Africa. It originates in Zambia and passes through several countries before reaching its mouth in Mozambique.
The other pairs are incorrectly matched:
- Pair 1 is incorrect: The Mekong flows through Southeast Asia and empties into the South China Sea, not the Andaman Sea.
- Pair 2 is incorrect: The Thames flows through London and empties into the North Sea, whereas the Irish Sea lies to the west of Great Britain.
Therefore, only pairs 3 and 4 are accurately matched with their respective drainage basins.
PROVENANCE & STUDY PATTERN
Full viewThis question is a hybrid of direct NCERT recall (Volga) and basic map visualization (Mekong/Thames). It punishes 'text-only' readers who memorize river names without tracing their path on a physical map. The Volga fact acts as the anchor to eliminate 50% of the options immediately.
This question can be broken into the following sub-statements. Tap a statement sentence to jump into its detailed analysis.
- Explicitly states where the Mekong ends: the Mekong Delta.
- The passage names the river’s terminus (Mekong Delta) rather than the Andaman Sea, implying the Mekong does not flow into the Andaman Sea.
- Defines the Andaman Sea as the eastern extension of the Bay of Bengal (a distinct sea region).
- Shows the Andaman Sea is a separate body of water; the Mekong’s listed terminus (Mekong Delta) is not identified as the Andaman Sea in the provided passages.
Explicitly lists the Mekong River among freshwaters contributing to the South China Sea region (Mekong River included in a list alongside South China Sea rivers).
A student could use a map to note the Mekong's mouth relative to the Andaman Sea versus the South China Sea to judge whether it flows into the Andaman Sea.
Identifies the Andaman Sea as a named body of water in the region (asks which water body separates Andaman from Nicobar islands), clarifying the Andaman Sea's geographic identity.
A student could locate the Andaman Sea on a map to compare its position with the Mekong delta to see if they coincide.
Shows that some rivers in northeastern India/Myanmar region (Manipur River) join larger Myanmar river systems (Irrawaddy), illustrating that regional drainage connects to seas east of the Indian subcontinent.
A student could trace regional river systems on a map (Irrawaddy, Mekong) to determine which sea each ultimately reaches and thus infer whether Mekong reaches the Andaman Sea.
Gives a general pattern that many rivers in South/SE Asia drain into specific nearby seas (Bay of Bengal or Arabian Sea), demonstrating that regional drainage tends to reach geographically proximate seas.
Using this pattern plus a map, a student can check whether the Mekong's geographic course makes the Andaman Sea a likely outlet compared with other nearby seas (e.g., South China Sea, Bay of Bengal).
- WorldAtlas entry specifically references the Thames River and its lower reaches.
- The snippet indicates the Thames reaches the sea via the Thames Estuary (the known outlet to the North Sea), contradicting an Irish Sea outflow.
- Britannica lists the River Thames and separately identifies the North Sea, linking the Thames to the North Sea contextually.
- This supports that the Thames flows to the North Sea rather than the Irish Sea.
Mentions the tidal nature of the mouth of the Thames and Port of London becoming important because of that tidal mouth—implies the Thames has an estuarine mouth connecting to the open sea.
A student could use a map to locate the Thames estuary and then check which open sea/sea basin that estuary opens into (e.g., North Sea vs Irish Sea).
Defines an estuary as a semi-enclosed coastal body with river(s) flowing into it and having a free connection with the open sea.
Apply this definition to the Thames estuary (from snippet 1) and then determine geographically which sea the estuary connects to on a map.
Explains that an estuary is the point where a river mouth enters the sea and is mixed with seawater and tides—reinforces that identifying the sea connected to a river mouth answers where the river flows.
Use the Thames estuary's location on a map to identify the specific sea basin receiving the Thames' waters.
Gives the example of Oxford on the Thames as a river port at the limit of navigation, illustrating that rivers have navigable reaches leading to their ocean-connected mouths.
Trace the river's navigable route downstream from Oxford on a map to its estuary and then see which sea it reaches.
States the general pattern that rivers discharge their waters into the nearest major sea or ocean (examples from India), suggesting one can infer a river's receiving sea by geographic position.
A student could locate the Thames on a map of the British Isles and, using proximity and orientation, infer whether its mouth faces the Irish Sea or another sea.
- Explicitly identifies the Volga as draining into the Caspian Sea.
- Describes the Volga as a major navigable waterway in Russia, linking it to the Caspian basin.
- Mentions connected canals (Volga-Moscow, Volga-Don) that contextualize Volga's role in regional drainage and navigation.
Describes the Mozambique current flowing between Mozambique and western Madagascar — evidencing that the coast of Mozambique borders the southern Indian Ocean.
A student could use a map to note that the Zambezi empties on the coast of Mozambique, and thus likely reaches the Indian Ocean waters indicated here.
Explains south Indian Ocean circulation around Madagascar and mentions the Mozambique/Agulhas branch — reinforcing that Mozambique is on the Indian Ocean side.
Combine this with a map showing the Zambezi basin location in southeastern Africa to infer the river’s outlet region relative to the Indian Ocean.
Gives a clear general rule: geography (location of mountain ranges/coasts) determines river flow direction and which sea/ocean they drain into.
Apply the same logic to southern Africa: identify local divides and coastlines on a map to judge whether the Zambezi’s course leads to the Indian Ocean.
Provides an example of a river (Indus) where the text explicitly states which sea it reaches, illustrating the type of source needed to confirm a river’s ocean outlet.
Use this as a template: locate authoritative sources or maps that state where the Zambezi ‘flows into’ just as the Indus example names the Arabian Sea.
- [THE VERDICT]: Manageable Sitter. Volga is verbatim in NCERT Class XII (Human Geo); Mekong and Thames are basic map logic (East vs West flow).
- [THE CONCEPTUAL TRIGGER]: World Drainage Systems & Ocean Outlets. Specifically, the 'Mouth of the River' location.
- [THE HORIZONTAL EXPANSION]: Danube → Black Sea; Rhine → North Sea; Po → Adriatic Sea; Rhone → Mediterranean; Tigris/Euphrates → Persian Gulf; Amur → Strait of Tartary; Orange River → Atlantic Ocean; Limpopo → Indian Ocean.
- [THE STRATEGIC METACOGNITION]: Never memorize a river in isolation. Always tag its 'Start' (Source) and 'End' (Mouth). Visualize the continental slope: e.g., The Indochina peninsula tilts South-East, so rivers there cannot flow West into the Andaman Sea.
Mekong is a major Southeast Asian river that drains into the South China Sea rather than the Andaman Sea.
High-yield for questions on river basins and coastal outlets in Southeast Asia; helps eliminate incorrect sea destinations in MCQs and map-based questions. Links to topics on delta formation, transboundary rivers and regional geography.
- Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 26: Tropical Cyclones > More Freshwater Flow Into The Northern Hemisphere > p. 369
Rivers of the Himalayas and the Peninsular plateau predominantly discharge into either the Bay of Bengal or the Arabian Sea depending on their slope and origin.
Essential for answering questions on Indian drainage patterns, physiographic controls on river courses, and delta/estuary formation. Useful for comparative questions and eliminating distractors about coastal outlets.
- INDIA PHYSICAL ENVIRONMENT, Geography Class XI (NCERT 2025 ed.) > Chapter 3: Drainage System > Important Drainage Patterns > p. 19
- CONTEMPORARY INDIA-I ,Geography, Class IX . NCERT(Revised ed 2025) > Chapter 3: Drainage > The Peninsular Rivers > p. 21
- INDIA PHYSICAL ENVIRONMENT, Geography Class XI (NCERT 2025 ed.) > Chapter 3: Drainage System > River Systems of the Peninsular Drainage > p. 24
The Western Ghats form the main water divide causing most peninsular rivers to flow east to the Bay of Bengal, while a few short rivers and the Narmada/Tapi flow west to the Arabian Sea.
Crucial for map questions and conceptual understanding of river directions in peninsular India; connects to topics on drainage basins, coastal geomorphology and regional water resources.
- CONTEMPORARY INDIA-I ,Geography, Class IX . NCERT(Revised ed 2025) > Chapter 3: Drainage > The Peninsular Rivers > p. 21
- Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 16: Fluvial Landforms and Cycle of Erosion > Parallel Drainage Pattern > p. 215
- INDIA PHYSICAL ENVIRONMENT, Geography Class XI (NCERT 2025 ed.) > Chapter 3: Drainage System > River Systems of the Peninsular Drainage > p. 24
An estuary is the coastal zone where a river enters the sea and mixes freshwater with seawater.
High-yield for questions on coastal geomorphology and port locations; clarifies how river mouths form sheltered bays and influence salinity gradients. Connects to tidal processes, ecosystems, and human uses like fisheries and navigation; enables answers about where rivers meet oceans and the consequences.
- Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 4: Aquatic Ecosystem > 4.7.L Charact€rs > p. 45
- Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 3: MAJOR BIOMES > Estuary Ecosystem > p. 27
Tides can make river mouths navigable and lead to the development of tidal ports at river mouths.
Important for economic and human geography topics on port location and transport; explains why major ports occur at certain river mouths and how tidal regimes affect navigation and urban development. Useful for linking physical processes to regional economy questions.
- Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 32: Ocean Movements Ocean Currents And Tides > Navigation > p. 507
- Certificate Physical and Human Geography , GC Leong (Oxford University press 3rd ed.) > Chapter 31: Settlements and Towns > Location of settlements > p. 318
Rivers discharge into specific seas or oceans depending on their drainage basins and flow directions.
Crucial for map-based and drainage-system questions; helps determine where major rivers terminate and how continental slopes and mountain origins control discharge direction. Enables tackling comparative questions about river mouths and regional hydrology.
- INDIA PHYSICAL ENVIRONMENT, Geography Class XI (NCERT 2025 ed.) > Chapter 3: Drainage System > Important Drainage Patterns > p. 19
- INDIA PHYSICAL ENVIRONMENT, Geography Class XI (NCERT 2025 ed.) > Chapter 3: Drainage System > DRAINAGE SYSTEM > p. 17
The Volga drains into the Caspian Sea, an enclosed inland sea, illustrating inland drainage behavior.
High-yield for drainage and water-budget topics; explains salt accumulation and limited ocean mixing in closed basins. Connects physical geography (salinity, evaporation) with river discharge and basin classification.
- FUNDAMENTALS OF HUMAN GEOGRAPHY, CLASS XII (NCERT 2025 ed.) > Chapter 7: Transport and Communication > The Volga Waterway > p. 65
- Certificate Physical and Human Geography , GC Leong (Oxford University press 3rd ed.) > Chapter 12: The Oceans > Salinity of the Ocean > p. 108
Since Volga (Caspian) was asked, look at the 'Five Seas of Russia' system connected by canals: White Sea, Baltic Sea, Caspian Sea, Sea of Azov, and Black Sea. Also, watch out for the Danube, which flows into the Black Sea and passes through 4 capital cities (Vienna, Bratislava, Budapest, Belgrade).
Use 'Continental Orientation' logic. London faces Europe (East), so the Thames must flow into the North Sea, not the Irish Sea (West). The Mekong runs through the Indochina peninsula; for it to reach the Andaman Sea (West), it would have to cross the Arakan Yoma mountain ranges, which is geologically impossible.
Mains GS-2 (IR): The Mekong's outlet is crucial for the 'South China Sea' dispute and 'Mekong-Ganga Cooperation'. Geography dictates the geopolitics—China controls the headwaters (Lancang), affecting the rice bowl of Vietnam at the delta.