Read the passage and answer the questions given below it.
A river fed by ice can look its healthiest just when its future is least secure. That is the puzzle of the Himalayan glaciers. The Bhagirathi, a headstream of the Ganga, flows from the snout of the Gangotri glacier, and many northern rivers draw on ice in their upper reaches. Survey after survey finds that most Himalayan glaciers are thinning and retreating.
Retreat, oddly, does not at first mean less water. A glacier that melts faster sends more water downstream, so a river may run fuller for years while the ice that feeds it shrinks. Scientists call the turning point ‘peak water’. After it, the melt begins to fall, because less ice is left to melt. The extra flow is not a sign of health. It is a store being spent.
Nor does this matter most in the monsoon. During the rains, the plains hardly need the glaciers, since rainfall dwarfs their share. It is in the hot, dry weeks before the monsoon, when fields are parched, that meltwater attenuates the effects of the shortage. The Indus basin, with its drier lowlands, leans on this supply far more heavily than the Ganga basin, where rain carries more of the load.
Retreat brings a quicker danger too. Meltwater often pools in lakes behind loose walls of rock and debris left by the glacier. If such a wall gives way, the lake can empty within hours, and the flood that follows, a glacial lake outburst flood, tears down the valley with little warning. None of this means the rivers will soon run dry. When peak water arrives differs from basin to basin, and for some rivers no one can yet say whether it has already passed.
The word ‘attenuates’, as used in the passage, means:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → makes less harsh or strong
Attenuate means to make something less harsh or strong.
- The passage says that in the dry weeks before the monsoon, meltwater “attenuates the effects of the shortage”. The water does not end the shortage. It makes it less severe.
- This fits the paragraph: the plains lean on meltwater most when fields are parched, or very dry. Example: The thick curtains attenuate the noise of the traffic outside.
Why the Other Options are Incorrect?
Option 1: puts off until a later time — Incorrect. Wrong meaning: This is the meaning of postpone. Example: The school had to postpone sports day because of the rain.
Option 2: makes slimmer in shape — Incorrect. Wrong meaning: This is another, older meaning of attenuate, used for shape. A shortage has no shape to make slimmer. Example: The potter’s hands attenuated the neck of the vase.
Option 4: makes more serious — Incorrect. Wrong meaning: This is the meaning of aggravate. Example: Scratching the bite will only aggravate the itch.