Question map
Which of the following are some important pollutants released by steel industry in India? 1. Oxides of sulphur 2. Oxides of nitrogen 3. Carbon monoxide 4. Carbon dioxide Select the correct answer using the code given below.
Explanation
Emission standards for steel plants define permissible limits for pollutants such as particulate matter (PM), sulphur dioxide (SO2), nitrogen oxides (NOx), and carbon monoxide (CO)[1], confirming that all three of these are important pollutants from the steel industry. Additionally, the incomplete burning of coal and coke in the steel industry can release carbon monoxide into the air[2].
While carbon dioxide is not always classified as a traditional "pollutant" in the same sense as toxic gases, carbon dioxide (CO₂) is the primary greenhouse gas emitted through human activities[3], and human activities like industry, transportation, and agriculture have released enormous amounts of these 'greenhouse gases'[4]. The steel industry, being energy-intensive and reliant on coal combustion, is a significant source of CO2 emissions.
Therefore, all four pollutants—oxides of sulphur, oxides of nitrogen, carbon monoxide, and carbon dioxide—are important pollutants released by the steel industry in India. The correct answer is option D (1, 2, 3 and 4).
Sources- [1] https://steel.gov.in/sites/default/files/2025-03/GSI%20Report.pdf
- [2] https://abhipedia.abhimanu.com/Article/1079/NDYyMzYz/Consider-the-following-pollutants-1-Oxides-of-sulfur-2-Particulate-Matter-3-Oxides-Minerals-
- [3] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 17: Climate Change > 12.3.2 Carbon Dioxide > p. 255
- [4] Exploring Society:India and Beyond ,Social Science-Class VII . NCERT(Revised ed 2025) > Chapter 3: Climates of India > Fossil fuels: > p. 64
PROVENANCE & STUDY PATTERN
Full viewThis question rewards 'Process Logic' over rote memorization. You don't need a government report on steel; you only need to know that steel plants burn coal/coke. If an industry burns fossil fuels, it automatically emits the 'Big 4' (SOx, NOx, CO2, CO). The strategy is to map Inputs (Coal) to Outputs (Emissions).
This question can be broken into the following sub-statements. Tap a statement sentence to jump into its detailed analysis.
- Statement 1: Are oxides of sulphur (SOx) among the important pollutants emitted by the steel industry in India?
- Statement 2: Are oxides of nitrogen (NOx) among the important pollutants emitted by the steel industry in India?
- Statement 3: Is carbon monoxide (CO) an important pollutant emitted by the steel industry in India?
- Statement 4: Is carbon dioxide (CO2) an important pollutant/greenhouse gas emitted by the steel industry in India?
- Explicitly names 'Sulphur Oxides' as a pollutant and lists 'industries' among its sources.
- Links SOx to industrial emissions and describes associated health effects, supporting inclusion of SOx in industrial pollutant lists.
- Identifies 'Sulphur Oxide' as emitted by 'thermal power plants, industries and vehicles', reinforcing that industries are a source of SOx.
- Provides effects of sulphur oxides on respiratory health, indicating their significance as industrial air pollutants.
- Lists inorganic pollutants specific to Iron & Steel, including sulphur-related compounds (sulphides), showing the steel sector emits sulfur-bearing pollutants.
- Connects the steel industry to a range of inorganic pollutants, supporting inference that sulfur oxides are plausible industrial emissions in this sector when combined with generic 'industries' sources above.
- Explicitly names 'industrial emissions' as a main source of nitrogen oxides.
- Directly links NOx production to industry-scale activities, which includes heavy industries such as steel.
- States that nitrogen oxide is produced from burning fuels (petrol, diesel, coal).
- Connects fuel combustion — a core process in steel plants — with NOx formation.
- Describes steel plants' use of coal and other fuel/chemical inputs.
- Notes that a steel plant 'releases large quantity of nitrogen' as a by-product, supporting an industry-level link to nitrogen emissions.
- Lists carbon monoxide (CO) alongside PM, SO2 and NOx as pollutants for which Indian authorities set emission standards for steel plants.
- States steel plants use Continuous Emissions Monitoring Systems (CEMS) to monitor key pollutants including CO, implying regulatory importance.
- Explicitly states that incomplete burning of coal and coke in the steel industry can release carbon monoxide into the air.
- Describes CO as a toxic pollutant from steel operations and notes it is among pollutants released by the steel industry in India.
States that many industrial processes and fossil-fuel combustion emit COx (text lists combustion and metal production such as iron and steel as sources).
A student could combine this with the basic fact that incomplete combustion of carbon fuels produces CO (as well as CO2) to suspect steel plants burning coal may emit CO.
Notes the steel industry depends on fossil fuel inputs and highlights shortages/usage of coking coal, implying substantial coal combustion in steel production.
Knowing coal combustion can produce CO under incomplete combustion, one could investigate whether Indian steel plants' fuel/combustion conditions favor CO formation.
Specifies that a major steel plant obtains coal from several coalfields, showing direct use of coal at steel facilities.
Combine with the combustion→CO link to assess whether on-site coal burning at such coastal/large plants could be a CO source locally.
Mentions steel plants produce byproducts from coal-related processing (coal-tar, benzol), indicating coal/coal-derivative processes are integral to operations.
A student could infer coal-processing steps and associated heating might lead to conditions (pyrolysis, incomplete combustion) that generate CO and then check emissions data.
Describes air pollution in Indian cities as significantly driven by smoke from vehicles and factories, situating industrial emissions as a recognized air-quality concern.
Use this to motivate looking up local air-quality inventories or monitoring near steel hubs to see if CO is listed among industrial pollutants.
- States that carbon dioxide (CO2) is the primary greenhouse gas emitted through human activities — establishes CO2 as the key industrial GHG.
- Provides the foundational claim that CO2 is the principal anthropogenic greenhouse gas relevant to industrial emissions.
- Explicitly lists 'industry' among human activities releasing greenhouse gases, linking industrial processes to CO2 emissions.
- Connects the general category of industry (which includes steel) to the mechanism of increased atmospheric CO2 and warming.
- Documents the presence and importance of iron and steel plants in India, identifying the sector subject to industrial emissions.
- When combined with snippets that link industry to CO2 emissions, supports the inference that Indian steel plants are a source of CO2.
- [THE VERDICT]: Sitter. Solvable by basic environmental chemistry found in NCERT Science or Shankar IAS (Chapter 5: Pollution).
- [THE CONCEPTUAL TRIGGER]: Anthropogenic Emission Sources (Combustion Chemistry).
- [THE HORIZONTAL EXPANSION]: Map pollutants to other key sectors: 1. Thermal Power: SOx, NOx, Mercury, Fly Ash. 2. Cement: CO2 (from Limestone), PM. 3. Fertilizer: Ammonia, Fluoride, NOx. 4. Refineries: VOCs, Benzene, SO2. 5. Vehicles: CO, NOx, Hydrocarbons.
- [THE STRATEGIC METACOGNITION]: Adopt the 'Input-Process-Output' model. Do not memorize lists. Ask: 'Does this industry burn coal?' Yes → SOx, NOx, Ash. 'Does it reduce ore with carbon?' Yes → CO, CO2. 'Is it high temperature?' Yes → NOx.
References explicitly name SOx and list 'industries' as a source, linking SOx to industrial emissions relevant to steel plants.
High-yield for environment questions: SOx are commonly tested as major industrial pollutants and for their health and acid-rain impacts. Connects to topics on industrial pollution sources, emission controls, and health/environmental effects. Learn definitions, common sources (thermal plants, industries, vehicles), and impacts; practise applying these to sector-specific questions.
- Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 5: Environmental Pollution > Fly ash notification zozr > p. 67
- Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 6: Environmental Degradation and Management > Consequences of Air Pollution > p. 40
One reference lists inorganic and organic pollutants specific to Iron & Steel, highlighting the industry's pollutant mix.
Important for answers on sectoral pollution in UPSC: helps quickly identify likely pollutants from metallurgical industries and link them to mitigation/regulation discussions. Study pollutant lists by industry and remember typical inorganic (metals, sulphur compounds) and organic effluents.
- Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 6: Environmental Degradation and Management > 6.32 Environment and Ecology > p. 37
References tie sulphur oxides to acid-gas effects on materials and health, showing why SOx emissions are significant.
Useful for policy and environment essays/answers: connects emission sources to consequences (corrosion, acid rain, health). Master cause–effect chains (SOx → acid deposition → material damage/health impacts) and relevant examples; practice framing impacts and mitigation in answers.
- Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 5: Environmental Pollution > f) Acid rain damage on Materials > p. 105
- Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 6: Environmental Degradation and Management > Consequences of Air Pollution > p. 40
Multiple references identify 'industry' or 'industrial emissions' as primary sources of nitrogen oxides, implying heavy industries (including steel) contribute to NOx pollution.
UPSC often asks about pollutant sources and sectoral responsibilities; mastering that industries are a key NOx source helps answer questions on pollution control, regulatory policy (e.g., sector-specific norms), and health impacts. Prepare by mapping pollutants to source sectors (transport, industry, agriculture) and studying mitigation measures.
- Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 19: Ozone Depletion > Sources > p. 269
- Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 6: Environmental Degradation and Management > Consequences of Air Pollution > p. 40
References link burning of coal, petrol and diesel to nitrogen oxide production—relevant because steel plants use coal and other fuels.
High-yield for questions on emission chemistry, sectoral pollution profiles, and mitigation (fuel switching, cleaner fuel norms). Connects to topics on energy sources, industrial processes, and emission norms (e.g., BS-VI). Study by linking fuel types to typical pollutant outputs and control technologies.
- Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 5: Environmental Pollution > Ozone. > p. 64
- Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 11: Industries > 5. Raurkela Iron and Steel Plant (Hindustan Steel Limited) > p. 34
Evidence lists major steel plants, their coal usage and mentions release of nitrogen by-products — making the steel sector relevant when discussing NOx/industrial emissions.
Useful for questions that require sector-specific pollution analysis (e.g., regional industrial clusters, environmental impact of PSUs/private plants). Learn by reviewing major industrial processes, typical emissions, and local environmental issues tied to plant locations.
- Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 11: Industries > Iron and Steel Plants in India > p. 28
- Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 11: Industries > 5. Raurkela Iron and Steel Plant (Hindustan Steel Limited) > p. 34
Reference [3] explicitly states that production of metals such as iron and steel produces 'CO e' emissions (i.e., carbon-equivalent/CO2e) via combustion and chemical processes.
High-yield for UPSC environment and industry questions: connects industrial processes, climate change (GHG inventory), and sectoral mitigation policy (e.g., steel sector decarbonisation). Mastery helps answer questions on emission sources, national commitments, and technology/policy measures. Study strategy: focus on sectoral emission drivers, mitigation options, and linkages to industrial policy.
- Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 17: Climate Change > The main sources > p. 256
- Indian Economy, Nitin Singhania .(ed 2nd 2021-22) > Chapter 12: Indian Industry > Major Industries: Roles and Challenges > p. 397
Solid Waste (Slag & Fly Ash). Since you now know the gaseous emissions, the next logical question is on solid by-products. Steel plants produce 'Blast Furnace Slag' (used in cement/roads) and 'Fly Ash' (from captive power plants). Watch for 'Ground Granulated Blast-furnace Slag (GGBS)'.
The 'Combustion Certainty' Rule. If a question asks about pollutants from a fossil-fuel intensive industry, and the options are basic oxides (CO, CO2, SOx, NOx), it is scientifically impossible to eliminate any of them without advanced filters (which the question doesn't specify). Assume presence unless the option is exotic (e.g., 'Radioactive isotopes' or 'CFCs').
Green Steel & CBAM (Mains GS3/GS2). Link these emissions to the EU's Carbon Border Adjustment Mechanism (CBAM). The EU taxes imports based on exactly these 'embedded emissions' (CO2). The solution is 'Green Steel' using Hydrogen instead of Coking Coal, which eliminates SOx/CO2.