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Q28 (IAS/2021) Environment & Ecology › Pollution & Conservation › Energy and emissions Official Key

With reference to furnace oil, consider the following statements : 1. It is a product of oil refineries. 2. Some industries use it to generate power. 3. Its use causes sulphur emissions into environment. Which of the statements given above are correct?

Result
Your answer: —  ·  Correct: D
Explanation

The correct answer is Option 4 (1, 2, and 3). Furnace oil, also known as fuel oil, is a dark, viscous residual product obtained during the distillation process in oil refineries (Statement 1).

Due to its high calorific value and cost-effectiveness, it is widely utilized in industrial sectors like cement, steel, and chemicals to generate power and heat for boilers and furnaces (Statement 2). However, furnace oil is characterized by high levels of nitrogen and sulphur. When combusted, it releases significant sulphur dioxide (SO2) and particulate matter into the atmosphere, contributing to environmental pollution and acid rain (Statement 3).

  • Statement 1: Correct; it is the "bottom of the barrel" product after lighter fractions are distilled.
  • Statement 2: Correct; many heavy industries rely on it for captive power generation.
  • Statement 3: Correct; it is notoriously high in sulphur, often exceeding 2% concentration.
How others answered
Each bar shows the % of students who chose that option. Green bar = correct answer, blue outline = your choice.
Community Performance
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PROVENANCE & STUDY PATTERN
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Don’t just practise – reverse-engineer the question. This panel shows where this PYQ came from (books / web), how the examiner broke it into hidden statements, and which nearby micro-concepts you were supposed to learn from it. Treat it like an autopsy of the question: what might have triggered it, which exact lines in the book matter, and what linked ideas you should carry forward to future questions.
Q. With reference to furnace oil, consider the following statements : 1. It is a product of oil refineries. 2. Some industries use it to g…
At a glance
Origin: Mixed / unclear origin Fairness: Moderate fairness Books / CA: 6.7/10 · 0/10

This is a classic 'Applied Science' question disguised as Geography. It doesn't require a PhD in Chemical Engineering; it requires connecting Class X Science (Fossil fuels = Sulphur) with basic Industrial Geography (Refineries make fuel). If you know crude oil is dirty and refineries separate it, the answer flows logically.

How this question is built

This question can be broken into the following sub-statements. Tap a statement sentence to jump into its detailed analysis.

Statement 1
Is furnace oil produced by oil refineries?
Origin: Weak / unclear Fairness: Borderline / guessy
Indirect textbook clues
Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 8: Energy Resources > Oil Refineries of India > p. 15
Strength: 5/5
“The oil refineries are the processing factories of crude-oil. The impurities from the crude oil are removed to obtain petroleum, diesel, kerosene, bitumen, and aviation fuel. Petroleum industry contributes over 15% of the GDP (2015–16). The main refineries of India, their year of commission and production capacity are given in (Fig. 8.5) (Table 8.6).”
Why relevant

Lists specific products produced by refineries (petroleum, diesel, kerosene, bitumen, aviation fuel), showing refineries separate crude into multiple fuel and hydrocarbon fractions.

How to extend

A student can note that refineries make a range of fuels and, using basic knowledge that 'furnace oil' is a heavy fuel oil fraction, infer it is plausibly one of those refinery products to verify.

NCERT. (2022). Contemporary India II: Textbook in Geography for Class X (Revised ed.). NCERT. > Chapter 5: Print Culture and the Modern World > Petroleum > p. 115
Strength: 4/5
“Petroleum or mineral oil is the next major energy source in India after coal. It provides fuel for heat and lighting, lubricants for machinery and raw materials for a number of manufacturing industries. Petroleum refineries act as a "nodal industry" for synthetic textile, fertiliser and numerous chemical industries. Most of the petroleum occurrences in India are associated with anticlines and fault traps in the rock formations of the tertiary age. In regions of folding, anticlines or domes, it occurs where oil is trapped in the crest of the upfold. The oil bearing layer is a porous limestone or sandstone through which oil may flow.”
Why relevant

Describes petroleum refineries as nodal industry producing fuels and feedstock for many uses, indicating refineries produce various fuel types from crude.

How to extend

Combine this with the fact that furnace oil is a fuel type to suspect it is produced at refineries and then check standard refinery product lists.

Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 8: Energy Resources > Pipelines > p. 14
Strength: 4/5
“Crude oil from oil-wells and finished products from refineries are generally transported through pipelines. Transportation of oil and petroleum through pipelines is cheap, effective, and considered to be safe. Looking at these advantages, a network of pipelines has been developed in India. Some of the important pipelines are as under:”
Why relevant

States that both crude oil and finished products from refineries are transported through pipelines, implying refineries output 'finished' fuel products ready for distribution.

How to extend

A student could use this to reason that common distributed fuels (including furnace oil if distributed similarly) originate at refineries and are piped to users or storage.

INDIA PEOPLE AND ECONOMY, TEXTBOOK IN GEOGRAPHY FOR CLASS XII (NCERT 2025 ed.) > Chapter 5: Mineral and Energy Resources > Iron Ore > p. 59
Strength: 3/5
“Mumbai High which lies 160 km off Mumbai was discovered in 1973 and production commenced in 1976. Oil and natural gas have been found in exploratory wells in Krishna-Godavari and Kaveri basin on the east coast. Oil extracted from the wells is crude oil and contains many impurities. It cannot be used directly. It needs to be refined. There are two types of refineries in India: (a) field-based and (b) market-based. Digboi is an example of fieldbased and Barauni is an example of marketbased refinery.”
Why relevant

Explains crude oil cannot be used directly and 'needs to be refined', and gives examples of refinery types, reinforcing that refining yields usable fuel products.

How to extend

Using the general rule that refining converts crude into usable fuels, a student can look up where heavy fuel oils fit in refinery output to assess whether furnace oil is included.

Statement 2
Do some industries use furnace oil to generate power?
Origin: Direct from books Fairness: Straightforward Book-answerable
From standard books
Certificate Physical and Human Geography , GC Leong (Oxford University press 3rd ed.) > Chapter 27: Fuel and Power > The uses of oil > p. 271
Presence: 5/5
“Our 'machine age' with its high-speed machines would grind to a standstill if lubricants were not available. 3. As a vital source of power. Vast amounts of mineral oil are being burnt daily in heaters, boilers and furnaces to provide power in factories and to generate thermal electricity. Its great calorific capacity and its convenience for handling and transporting has made petroleum the most extensively used fuel. 4. The many uses of its by-products. Kerosene has long been a domestic fuel for cooking, lighting and heating. Bitumen or asphalt is used for roofing, road-surfacing and water-proofing purposes. Paraffin and wax are used as illuminants and lubricants and for the manufacture of candles, seals and polishes”
Why this source?
  • Explicitly notes mineral/petroleum oil is burnt in heaters, boilers and furnaces to provide power in factories.
  • Connects burning oil in furnaces directly to generation of thermal electricity used by industry.
Certificate Physical and Human Geography , GC Leong (Oxford University press 3rd ed.) > Chapter 27: Fuel and Power > Uses and advantages > p. 273
Presence: 4/5
“It can be conveniently used in kitchens, furnaces, and radiators for heating and is without ashes or residue. In factories, offices and homes, a flick of the finger brings light in darkness almost instantly. It preserves food in refrigerators or deep-freezers. It is difficult to imagine what would happen if there were a power failure in the world for just a few hours! 2. Its unlimited degree of divisibility. By the use of simple mechanical devices such as transformers, electrical energy can be adjusted from a fraction of a watt to thousands of watts per hour. It is thus indispensable in modern complex manufactures where the control of speed in machines or in furnaces is precise to a fraction of a second.”
Why this source?
  • States oil can be conveniently used in furnaces and radiators for heating, implying industrial furnace use.
  • Supports the practical use of oil-based fuels for industrial heating applications.
NCERT. (2022). Contemporary India II: Textbook in Geography for Class X (Revised ed.). NCERT. > Chapter 5: Print Culture and the Modern World > Rock Minerals > p. 115
Presence: 4/5
“Thermal electricity is generated by using coal, petroleum and natural gas. The thermal power stations use non-renewable fossil fuels for generating electricity.”
Why this source?
  • Identifies petroleum as one of the fuels used to generate thermal electricity.
  • Links petroleum fuel use to power generation generally, reinforcing industrial power use of oil.
Statement 3
Does the combustion or use of furnace oil cause sulphur emissions into the environment?
Origin: Direct from books Fairness: Straightforward Book-answerable
From standard books
Science , class X (NCERT 2025 ed.) > Chapter 4: Carbon and its Compounds > Activity 4.4 > p. 70
Presence: 5/5
“mixture is burnt to give a clean blue flame. If you observe the bottoms of cooking vessels getting blackened, it means that the air holes are blocked and fuel is getting wasted. Fuels such as coal and petroleum have some amount of nitrogen and sulphur in them. Their combustion results in the formation of oxides of sulphur and nitrogen which are major pollutants in the environment.”
Why this source?
  • Identifies petroleum (a fuel class that includes furnace oil) as containing sulphur.
  • States that combustion of such fuels produces oxides of sulphur, directly linking fuel burning to sulphur emissions.
Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 29: Environment Issues and Health Effects > b) Yokkaichi asthma > p. 416
Presence: 5/5
“• r Disease occurred in the city of Yokkaichi in Mie Prefecture, Japan between 1960 and 1972. • The burning of petroleum and crude oil released large quantities of sulfur oxide that caused severe smog, resulting in severe cases of chronic obstructive pulmonary disease, chronic bronchitis, pulmonary emphysema, and bronchial asthma among the local inhabitants.”
Why this source?
  • Gives a concrete historical example where burning petroleum/crude oil released large quantities of sulfur oxides.
  • Links sulfur oxide emissions from oil combustion to serious public-health impacts, confirming the pollutant effect.
Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 2: Functions of an Ecosystem > b) Sulphur Cycle > p. 21
Presence: 4/5
“(b) Sulphur Cycle The sulphur reservoir is in the soil and sediments where it is locked in organic (coal, oil and peat) and inorganic deposits (pyrite rock and sulphur rock) in the form of sulphates, sulphides and organic sulphur. It is released by weathering of rocks, erosional runoff and decomposition of organic matter and is carried to terrestrial and aquatic ecosystems in salt solution. The sulphur cycle is mostly sedimentary except two of its compounds, hydrogen sulphide (H,S) and sulphur dioxide (SO,) add a gaseous component to its normal sedimentary cycle. Sulphur enters the atmosphere from several sources, including volcanic eruptions, combustion of fossil fuels, from the surface of ocean and from gases released by decomposition.”
Why this source?
  • Explains that sulphur enters the atmosphere from combustion of fossil fuels, providing the broader cycle context.
  • Specifies gaseous sulphur compounds (e.g., SO2) as atmospheric components produced by such processes.
Pattern takeaway: UPSC loves the 'Dirty Fuels' theme. They previously asked about Petcoke (2018/19 context) and Coal Ash. The pattern is: Identify a specific industrial fuel → Ask its source → Ask its application → Ask its pollutant profile.
How you should have studied
  1. [THE VERDICT]: Conceptual Sitter. Solvable via NCERT Science Class X (Carbon & Compounds) + GC Leong (Ch 27). No obscure book needed.
  2. [THE CONCEPTUAL TRIGGER]: Downstream Petroleum Sector & Industrial Pollution. Specifically, the 'Bottom of the Barrel' products (Heavy Oils).
  3. [THE HORIZONTAL EXPANSION]: Memorize the Refinery Distillation Column hierarchy: Gases (LPG) → Light Distillates (Petrol/Naphtha) → Middle Distillates (Kerosene/Diesel) → Heavy Ends (Furnace Oil/Lubricants) → Residue (Bitumen/Petcoke). Rule: Heavier = More Sulphur/Pollution.
  4. [THE STRATEGIC METACOGNITION]: Do not just map where oil is found. Study the *lifecycle* of a barrel of crude: What products come out? Who uses them (Transport vs. Industry)? What is the environmental cost (SOx/NOx)? This 'Resource-to-Residue' framework solves 90% of energy questions.
Concept hooks from this question
📌 Adjacent topic to master
S1
👉 Refinery outputs: crude oil → petroleum products
💡 The insight

Oil refineries remove impurities from crude oil and produce refined petroleum products such as diesel, kerosene, bitumen and aviation fuel.

High-yield for UPSC: clarifies which fuels and materials originate from refining versus direct extraction; connects energy resources, industrial geography and economic contributions of the petroleum sector; helps answer questions about product origin, refining role and downstream industries.

📚 Reading List :
  • Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 8: Energy Resources > Oil Refineries of India > p. 15
  • INDIA PEOPLE AND ECONOMY, TEXTBOOK IN GEOGRAPHY FOR CLASS XII (NCERT 2025 ed.) > Chapter 5: Mineral and Energy Resources > Iron Ore > p. 59
  • NCERT. (2022). Contemporary India II: Textbook in Geography for Class X (Revised ed.). NCERT. > Chapter 5: Print Culture and the Modern World > Petroleum > p. 115
🔗 Anchor: "Is furnace oil produced by oil refineries?"
📌 Adjacent topic to master
S1
👉 Types and location of refineries
💡 The insight

Refineries can be field-based or market-based and are sited near oilfields, at ports of export, or at ports of import.

Useful for questions on industrial location and regional development; links to resource distribution, transport economics and planning; helps eliminate options about where refineries are likely to be established.

📚 Reading List :
  • Certificate Physical and Human Geography , GC Leong (Oxford University press 3rd ed.) > Chapter 27: Fuel and Power > Oil Refining > p. 269
  • INDIA PEOPLE AND ECONOMY, TEXTBOOK IN GEOGRAPHY FOR CLASS XII (NCERT 2025 ed.) > Chapter 5: Mineral and Energy Resources > Iron Ore > p. 59
🔗 Anchor: "Is furnace oil produced by oil refineries?"
📌 Adjacent topic to master
S1
👉 Transport of crude and finished petroleum products
💡 The insight

Crude oil and finished products are commonly transported through pipelines because this mode is cheap, effective and considered safe.

Relevant for logistics and infrastructure questions in the energy sector; connects to pipeline networks, distribution of fuels, and regional connectivity issues; enables analysis of supply-chain choices and policy implications.

📚 Reading List :
  • Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 8: Energy Resources > Pipelines > p. 14
🔗 Anchor: "Is furnace oil produced by oil refineries?"
📌 Adjacent topic to master
S2
👉 Petroleum as a fuel for thermal electricity
💡 The insight

Petroleum (including furnace-type oils) is used to generate thermal electricity and to power industrial boilers and furnaces.

High-yield for questions on energy sources and power generation; connects to power-sector policy, thermal vs. renewable generation debates, and environmental implications of fossil fuels. Mastery helps answer questions on energy mix, electricity generation methods, and industrial energy dependence.

📚 Reading List :
  • Certificate Physical and Human Geography , GC Leong (Oxford University press 3rd ed.) > Chapter 27: Fuel and Power > The uses of oil > p. 271
  • NCERT. (2022). Contemporary India II: Textbook in Geography for Class X (Revised ed.). NCERT. > Chapter 5: Print Culture and the Modern World > Rock Minerals > p. 115
🔗 Anchor: "Do some industries use furnace oil to generate power?"
📌 Adjacent topic to master
S2
👉 Oil-fired furnaces and boilers in industry
💡 The insight

Industries employ oil in heaters, boilers and furnaces to produce heat and mechanical/thermal power for factory processes.

Useful for questions on industrial processes, energy inputs for manufacturing, and cost/environment trade-offs. Links to topics on industrial energy efficiency, fuel substitution, and locational decisions for energy-intensive units.

📚 Reading List :
  • Certificate Physical and Human Geography , GC Leong (Oxford University press 3rd ed.) > Chapter 27: Fuel and Power > The uses of oil > p. 271
  • Certificate Physical and Human Geography , GC Leong (Oxford University press 3rd ed.) > Chapter 27: Fuel and Power > Uses and advantages > p. 273
🔗 Anchor: "Do some industries use furnace oil to generate power?"
📌 Adjacent topic to master
S2
👉 Energy supply as an industrial locational factor
💡 The insight

Access to reliable energy sources (coal, hydro, petroleum) influences where power‑intensive industries locate.

Relevant to economic geography and industrial policy questions; helps explain spatial distribution of industries like aluminium smelting and steel, and ties into infrastructure and regional development planning.

📚 Reading List :
  • FUNDAMENTALS OF HUMAN GEOGRAPHY, CLASS XII (NCERT 2025 ed.) > Chapter 5: Secondary Activities > Access to Sources of Energy > p. 38
  • Certificate Physical and Human Geography , GC Leong (Oxford University press 3rd ed.) > Chapter 28: Manufacturing Industry and The Iron and Steel Industry > Factors of Industrial Location > p. 281
🔗 Anchor: "Do some industries use furnace oil to generate power?"
📌 Adjacent topic to master
S3
👉 Sulphur in fossil fuels and formation of sulphur oxides
💡 The insight

Fossil fuels contain sulphur and burning them forms sulphur oxides (SOx).

High-yield for questions on air pollution and fuel characteristics; links fuel composition to pollutant chemistry and environmental outcomes like acidification. Useful across topics: energy sources, pollution control, and environmental impacts.

📚 Reading List :
  • Science , class X (NCERT 2025 ed.) > Chapter 4: Carbon and its Compounds > Activity 4.4 > p. 70
  • Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 2: Functions of an Ecosystem > b) Sulphur Cycle > p. 21
🔗 Anchor: "Does the combustion or use of furnace oil cause sulphur emissions into the envir..."
🌑 The Hidden Trap

Petcoke (Petroleum Coke). It is the solid residue from oil refining (sibling to Furnace Oil). It has higher calorific value than coal but extremely high sulphur content. Often used in cement kilns. Expect a comparison Q: 'Natural Gas vs. Petcoke vs. Furnace Oil'.

⚡ Elimination Cheat Code

Use 'Literalism & Generalization'.
1. 'Furnace Oil'—where else would an industrial oil come from if not a refinery? (Mines? Trees? No). -> Statement 1 is True.
2. 'Some industries'—this is a 'Possibility Statement'. Unless it's physically impossible, it's True. -> Statement 2 is True.
3. It is a fossil fuel. All fossil fuels contain sulphur. Burning them releases SOx. -> Statement 3 is True.

🔗 Mains Connection

Mains GS-3 (Environment vs. Economy): The use of Furnace Oil/Petcoke highlights the conflict between industrial cost-cutting (cheap dirty fuel) and public health (Air Pollution). Connect this to the Supreme Court's ban on FO/Petcoke in NCR and the push for 'Gas-based Economy' (shifting to LNG).

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