SSC CGL 2024 Tier-I · 10 September 2024, Shift 3 · General Awareness · Question 6 of 100

Text as printed on a candidate's response sheet for this shift; answer per SSC's tentative key as marked on that sheet. Solution last reviewed 6 September 2026.

Where this paper and its answers come from

SSC does not publish CGL question papers or a public answer key. The questions and options here are reproduced as printed on a candidate's own response sheet for this shift — the Commission's text, unchanged. Each answer is SSC's tentative key as marked on that sheet; SSC allowed challenges to it and never publishes a final key. The solutions are written by UnlockIAS.

As of 2021, which is the world's largest drainage basin with an area of about 70,00,000 km 2 ?

(a)Amazon basin
(b)Congo basin
(c)Amur basin
(d)Nile basin

Answer

Why

Correct — A. The Amazon basin drains about 70,00,000 sq km of South America, the largest catchment of any river system on earth.

It also carries the greatest discharge — more water reaches the sea from the Amazon than from any other river, because the equatorial belt feeds it rain all year.

The basin covers most of Brazil and reaches into Peru, Colombia, Bolivia, Ecuador and Venezuela. Note that basin area and river length are two different rankings, and this stem asks for area.

Why the others are wrong

(b)
Congo basin — The Congo basin is the world's second largest and second by discharge. Second is not first, and it is a long way behind the Amazon on catchment area.
(c)
Amur basin — The Amur drains north-eastern Asia along the Russia-China border. Its basin is a fraction of the Amazon's and it is not in contention for the largest.
(d)
Nile basin — The Nile is famous for length, not for catchment. Much of its basin is desert, so it discharges only a small fraction of the Amazon's water.

Concept

A drainage basin is the whole area drained by a river and its tributaries, bounded by a watershed — the ridge line that sends rain one way or the other.

Three separate rankings get muddled in exam halls: length of the main river, discharge of water, and area of the basin. The Amazon leads on discharge and basin area.

Its size follows from position. An equatorial basin receives convectional rain through the year, so tributaries stay full and the system drains a continent-sized area.

The stem writes the figure in the Indian system as 70,00,000, which is seventy lakh, or seven million sq km. Read the commas before you compare the number to anything you have memorised.

Key facts

The Amazon has the world's largest drainage basin, about 70,00,000 sq km.
The Amazon also has the highest discharge of any river in the world.
The Congo basin is the second largest in the world.
The Nile's usual superlative is length, not basin area or discharge.

Study next

World rivers ranked three ways — length, discharge and basin areaEquatorial climate and the Amazon rainforestIndian river basins — the Ganga basin as the largest in India

Common traps

Marking the Nile because it is the longest river, merging two different superlatives.
Misreading 70,00,000 in the Indian system as seven lakh instead of seventy lakh.

The stem hands you the area and asks for the river, so the number is a confirmation, not the work.

SSC asks world rivers beside Indian ones — east-flowing peninsular rivers at 18 Sep 2024, 12:30, GA Q.7 and west-flowing ones at 18 Sep 2024, 09:00, GA Q.13.

Related PYQs

No directly related past PYQ was found.