SSC CGL 2025 Tier-I · 21 September 2025, Shift 3 · General Awareness · Question 8 of 100

We transcribed this text from the pictures on a candidate's response sheet for this shift; the answer is the key SSC colour-marked on that sheet. Solution last reviewed 11 September 2026.

Where this paper and its answers come from

SSC does not publish CGL question papers or a public answer key. From 2025 the candidate response sheet prints every question and option as a picture, so the text here is transcribed from those pictures for this shift and checked against them independently; where the layout carries meaning, the picture is shown as well. Each answer is the key SSC colour-marked on that sheet. SSC released a tentative key for challenge and later its final one, both only to candidates behind a login, and the sheet does not say which of the two it carries. The solutions are written by UnlockIAS.

In India, which of these geological formations hosts the most significant groundwater reservoirs for large-scale and extensive development?

(a)Unconsolidated Formation
(b)Semi-Consolidated Formation
(c)Fissured Formations
(d)Consolidated Formations

Answer

Why

Correct — A. Unconsolidated formations are loose sediments such as sand, silt and gravel. Their open pores both store water and let it flow to wells.

In India the great example is the alluvium of the Indo-Gangetic and Brahmaputra plains, deep and continuous across the north. That is where groundwater can be drawn on a large scale → option (a).

Why the others are wrong

(b)
Semi-Consolidated Formation — Semi-consolidated rocks are partly cemented sediments. Cement fills part of the pore space, so they yield less water and over smaller areas than loose alluvium.
(c)
Fissured Formations — Fissured formations are hard rocks that hold water only in cracks and joints. Those openings are patchy, so yields are small and hard to predict.
(d)
Consolidated Formations — Consolidated formations are hard rocks such as granite and basalt. Their water sits in weathered layers and fractures, which suits local wells, not extensive development.

Concept

Groundwater lives in two kinds of space. In porous material it fills the gaps between grains. In hard rock it fills only fissures: cracks, joints and weathered zones.

Unconsolidated sediments are the most porous and the most continuous. Semi-consolidated ones are partly cemented. Consolidated rocks, such as the granites, gneisses and basalts of much of peninsular India, depend on fissures.

The options mix two ways of naming rock. 'Consolidated' and 'fissured' largely describe the same hard rock: one names its state, the other how water moves in it. Neither matches the thick, loose alluvium of the plains.

Key facts

The Indo-Gangetic Plain is the world's largest expanse of uninterrupted alluvium.
Unconsolidated sediments such as sand, silt and gravel store water in the pores between grains.
Hard, consolidated rocks hold water only in fractures, joints and weathered zones.
The Deccan basalts and the granites and gneisses of the peninsula are consolidated hard rocks.

Study next

Confined and unconfined aquifersGroundwater depletion in north-west IndiaAtal Bhujal Yojana for community groundwater management

Common traps

Reading 'consolidated' as 'solid and so dependable': for groundwater, loose sediment is the better store.
Treating fissured and consolidated as rival answers: both describe hard rock that holds water only in cracks.

Here hydrogeology is asked through its terms rather than its places. Tie each formation to a region: the alluvial plains for unconsolidated sediment, the Deccan and the peninsular shield for hard rock.

Related PYQs

No directly related past PYQ was found.

Topic: Geography — all 135 SSC CGL questions on it, every solved shift.