UPSC Prelims 2021 Q18: Environment & Ecology – Pollution & Waste Management
- (a) 1 and 2 only
- (b) 2 and 3 only
- (c) 1 and 3 only
- (d) 1, 2 and 3
Answer: (d) 1, 2 and 3
Explanation
Furnace Oil: Origin, Uses and Emissions
| Statement | Claim | Verdict | Detail |
|---|---|---|---|
| 1 | Product of oil refineries | TRUE | Furnace oil (also called Fuel Oil or Bunker C) is a heavy residue from petroleum refining - what remains after lighter fractions (petrol, diesel, kerosene) are extracted. |
| 2 | Some industries use it to generate power | TRUE | Used in captive power plants, ships (bunker fuel), boilers, cement plants, ceramic industry, glass manufacture and thermal power stations. |
| 3 | Its use causes sulphur emissions | TRUE | Furnace oil has high sulphur content (2-4%) vs diesel (~0.05%). Burning it releases SO2, contributing to acid rain and PM pollution. India banned high-sulphur furnace oil in NCR after 2017. |
All three statements are correct.
Answer: (d) 1, 2 and 3.
Why each option is right or wrong
- (a) Incorrect. Statement 3 (sulphur emissions) is also correct - furnace oil is high in sulphur.
- (b) Incorrect. Statement 1 (refinery product) is also true.
- (c) Incorrect. Statement 2 (power generation use) is also true.
- (d) CORRECT. All three are true - furnace oil is a refinery residue (1), used for industrial power (2), and emits sulphur (3). NCR banned it in 2017 for pollution.
Key point
Furnace oil = heavy refinery residue with 2-4% sulphur. Used in industrial boilers, ships (bunker fuel), captive power. Emits SO2 - contributes to acid rain. Banned in Delhi NCR since 2017 for air quality reasons.
Remember
Furnace oil is (1) a product of oil refineries (heavy residue), (2) used by some industries to generate power (captive power, boilers, ships) and (3) causes sulphur emissions (2-4% S content, banned in Delhi NCR 2017). All three statements are correct.
Common mistakes
- Confusing furnace oil with diesel or petrol. Furnace oil is HEAVIER and dirtier, with high sulphur content.
- Not knowing the 2017 NCR ban on furnace oil (and petcoke) by Supreme Court for pollution control.
- Missing that IMO's 2020 rule capped ship bunker fuel sulphur at 0.5% (from 3.5%) - major maritime pollution reform.
Exam tip
Refinery fraction ladder (light to heavy): LPG - Naphtha - Petrol - Kerosene - Diesel - Fuel Oil (Furnace Oil) - Bitumen. Sulphur content rises with heaviness. IMO 2020 rule and India's BS-VI norms (2020) target sulphur reduction.
Sources
- Bureau of Indian Standards — IS 1593: Furnace Oil — Specification
- Supreme Court Order on Furnace Oil ban in NCR (October 2017)