UPSC Prelims 2025 GS Paper I · Q4 of 99 Environment & Ecology medium

Consider the following : I. Cigarette butts II. Eyeglass lenses III. Car tyres How many of them contain plastic?

  1. (a) Only one
  2. (b) Only two
  3. (c) All the three ✓ UPSC's answer
  4. (d) None

Why the answer is (c)

• Cigarette filters are made of cellulose acetate, a plastic fibre; discarded butts are the single most littered plastic item in the world and take years to degrade — I contains plastic.

• Modern eyeglass lenses are mostly plastics — CR-39 (allyl diglycol carbonate), polycarbonate or high-index resins — chosen because they are lighter and shatter-resistant compared with glass — II contains plastic.

• Car tyres are made of synthetic rubber (a petroleum-derived polymer) blended with natural rubber; tyre wear is a major source of microplastic pollution — III contains plastic.

• All three items contain plastic, option (c).

• The question tests awareness that plastics hide in everyday objects not usually thought of as 'plastic'.

Why the other options are wrong

(a) Only one
All three items, not one, contain plastic polymers.
(b) Only two
All three contain plastic; none can be excluded.
(d) None
Cellulose acetate, polycarbonate and synthetic rubber are all plastics.

Asked in the GS Paper I of the UPSC Civil Services Preliminary Examination 2025, held on 25 May 2025. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.

Reading the answer is not the same as getting it right under a clock. Practise this question with UPSC's negative marking, and anything you miss goes into an error notebook until you get it right twice.

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