Pollution

11. In the context of WHO Air Quality Guidelines, consider the following s

In the context of WHO Air Quality Guidelines, consider the following statements :

  • The 24-hour mean of PM$_{2.5}$ should not exceed 15 $\mu$g/m$^3$ and annual mean of PM$_{2.5}$ should not exceed 5 $\mu$g/m$^3$.
  • In a year, the highest levels of ozone pollution occur during the periods of inclement weather.
  • PM$_{10}$ can penetrate the lung barrier and enter the bloodstream.
  • Excessive ozone in the air can trigger asthma.

Which of the statements given above are correct ?

1, 3 and 4
1 and 4 only
2, 3 and 4
1 and 2 only
This question was previously asked in
UPSC IAS – 2022
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The correct option is B, as statements 1 and 4 are correct.
Statement 1 is correct. The 2021 WHO Air Quality Guidelines recommend a 24-hour mean of PM$_{2.5}$ not exceeding 15 $\mu$g/m$^3$ and an annual mean not exceeding 5 $\mu$g/m$^3$.
Statement 2 is incorrect. Ground-level ozone is formed through photochemical reactions involving sunlight, NOx, and VOCs. High concentrations typically occur during hot, sunny weather with stagnant air, not during inclement weather which tends to break down or disperse pollutants.
Statement 3 is incorrect. While both PM$_{10}$ and PM$_{2.5}$ are harmful, smaller particles pose a greater health risk because they can penetrate deeper. PM$_{2.5}$ can reach the deep lung tissue and even enter the bloodstream. PM$_{10}$ mainly deposits in the upper respiratory tract and larger airways; crossing the lung barrier into the bloodstream is less characteristic of PM$_{10}$ as a whole compared to PM$_{2.5}$ and ultrafine particles.
Statement 4 is correct. Excessive exposure to ground-level ozone is a known respiratory irritant and can trigger or worsen asthma symptoms, causing coughing, wheezing, and difficulty breathing.
The WHO guidelines provide evidence-based recommendations for air quality levels to protect public health. Many countries have national air quality standards, which may differ from the WHO guidelines.

12. Consider the following : Carbon monoxide Nitrogen oxide Ozone Sul

Consider the following :

  • Carbon monoxide
  • Nitrogen oxide
  • Ozone
  • Sulphur dioxide

Excess of which of the above in the environment is/are cause(s) of acid rain ?

1, 2 and 3
2 and 4 only
4 only
1, 3 and 4
This question was previously asked in
UPSC IAS – 2022
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The correct answer is B) 2 and 4 only.
Acid rain is primarily caused by atmospheric pollutants, specifically sulfur dioxide (SO₂) and nitrogen oxides (NOx). These gases react with water, oxygen, and other chemicals in the atmosphere to form sulfuric acid and nitric acid.
Statement 1 (Carbon monoxide) is incorrect. Carbon monoxide (CO) is a pollutant but does not cause acid rain.
Statement 2 (Nitrogen oxide) is correct. Nitrogen oxides (NOx, including NO and NO₂) are major precursors to nitric acid formation in acid rain.
Statement 3 (Ozone) is incorrect. Ozone (O₃) is a secondary pollutant and a greenhouse gas. While it can contribute to the oxidation processes that form acid rain from SO₂ and NOx, it is not a precursor acid gas itself and is not considered a primary cause in the same way as SO₂ and NOx.
Statement 4 (Sulphur dioxide) is correct. Sulphur dioxide (SO₂) is a major precursor to sulfuric acid formation in acid rain.
The main sources of SO₂ and NOx emissions are the burning of fossil fuels (coal, oil, natural gas) in power plants, industries, and vehicles. Acid rain can harm forests, lakes, streams, and damage buildings and monuments.

13. Consider the following statements : Other than those made by humans,

Consider the following statements :

  • Other than those made by humans, nanoparticles do not exist in nature.
  • Nanoparticles of some metallic oxides are used in the manufacture of some cosmetics.
  • Nanoparticles of some commercial products which enter the environment are unsafe for humans.

Which of the statements given above is/are correct ?

1 only
3 only
1 and 2
2 and 3
This question was previously asked in
UPSC IAS – 2022
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The correct answer is D) 2 and 3.
Statement 1 is incorrect. Nanoparticles occur widely in nature, resulting from various natural processes such as volcanic eruptions, forest fires, sea spray, and even biological processes (e.g., formation of magnetite crystals in bacteria).
Statement 2 is correct. Nanoparticles of metallic oxides, such as titanium dioxide (TiO₂) and zinc oxide (ZnO), are commonly used in cosmetics, particularly in sunscreens, due to their ability to absorb and scatter UV light.
Statement 3 is correct. There are ongoing concerns about the potential environmental and health risks associated with nanoparticles from commercial products entering the environment, due to their small size, high surface area, and unique properties which can lead to different biological interactions and potential accumulation in tissues.
Research on the safety and environmental impact of manufactured nanoparticles is an active area of study. Regulatory bodies are developing guidelines and assessments for products containing nanomaterials.

14. Magnetite particles, suspected to cause neurodegenerative problems, ar

Magnetite particles, suspected to cause neurodegenerative problems, are generated as environmental pollutants from which of the following?

  • 1. Brakes of motor vehicles
  • 2. Engines of motor vehicles
  • 3. Microwave stoves within homes
  • 4. Power plants
  • 5. Telephone lines

Select the correct answer using the code given below.

1, 2, 3 and 5 only
1, 2 and 4 only
3, 4 and 5 only
1, 2, 3, 4 and 5
This question was previously asked in
UPSC IAS – 2021
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Magnetite (Fe3O4) particles are a form of iron oxide that can be generated from various industrial and environmental processes, particularly those involving high temperatures or friction/wear of ferrous materials. Recent research has linked exposure to fine airborne magnetite particles to potential neurodegenerative health risks.
Let’s examine the potential sources:
1. Brakes of motor vehicles: Brake pads and rotors (often made of cast iron, rich in iron) undergo friction at high temperatures during braking. This process releases wear particles, a significant portion of which are iron oxides, including magnetite. This is a known source of airborne particulate matter in urban environments.
2. Engines of motor vehicles: Internal combustion engines operate at high temperatures, and combustion processes can produce various metal oxides as part of particulate emissions. Friction within the engine can also contribute wear particles. While complex, motor vehicle exhaust is a source of fine metallic particles.
3. Microwave stoves within homes: Microwave ovens heat food using electromagnetic radiation. They do not involve combustion or significant friction/wear in a manner that would generate airborne magnetite particles as an environmental pollutant.
4. Power plants: Combustion of fossil fuels (especially coal and heavy fuel oil) in power plants involves high temperatures and the burning of materials containing trace metals, including iron. Power plants are a significant source of various particulate emissions, including metal oxides like magnetite.
5. Telephone lines: Traditional copper telephone lines are made of copper, not iron. Modern fiber optic cables are made of glass/plastic. Neither involves processes that would generate airborne magnetite particles.
Based on the known sources of magnetite particles from combustion and friction/wear processes, brakes of motor vehicles, engines of motor vehicles, and power plants are plausible sources. Microwave stoves and telephone lines are not.
Airborne magnetite particles are often generated from high-temperature combustion or friction and wear involving iron-containing materials.
Other sources of environmental magnetite particles can include industrial processes like welding, mining activities, and even natural sources like soil dust (though anthropogenic sources are often more directly linked to neurodegenerative concerns). Research on the precise links between environmental magnetite exposure and neurodegenerative diseases like Alzheimer’s is ongoing but suggests a potential connection for ultra-fine particles entering the brain.

15. With reference to furnace oil, consider the following statements : 1

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?

1 and 2 only
2 and 3 only
1 and 3 only
1, 2 and 3
This question was previously asked in
UPSC IAS – 2021
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The correct option is D. All three statements about furnace oil are correct.
– Furnace oil is a residual fuel obtained during the refining of crude petroleum. It is the heaviest commercial fuel oil. Statement 1 is correct.
– Industries, including power plants, factories, and ships, use furnace oil as fuel in boilers and furnaces to generate heat and power. Statement 2 is correct.
– Furnace oil typically has a high sulfur content (residual fuel oils contain the sulfur that was not removed during refining). Burning furnace oil releases significant amounts of sulfur dioxide (SO2) into the atmosphere, contributing to air pollution and acid rain. Statement 3 is correct.
Due to its high sulfur content and resulting pollution, regulations around the use of furnace oil have become stricter globally, leading to a shift towards low-sulfur fuels or alternative energy sources in many sectors.

16. Why is there a concern about copper smelting plants? 1. They may rel

Why is there a concern about copper smelting plants?

  • 1. They may release lethal quantities of carbon monoxide into environment.
  • 2. The copper slag can cause the leaching of some heavy metals into environment.
  • 3. They may release sulphur dioxide as a pollutant.

Select the correct answer using the code given below.

1 and 2 only
2 and 3 only
1 and 3 only
1, 2 and 3
This question was previously asked in
UPSC IAS – 2021
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The correct option is B. Statements 2 and 3 are significant concerns associated with copper smelting plants, while statement 1 is less characteristic as a primary lethal pollution concern compared to sulphur dioxide emissions.
– Copper smelting often involves processing sulfide ores, leading to the release of large quantities of sulfur dioxide (SO2), a major air pollutant causing acid rain and respiratory issues. Statement 3 is correct.
– Copper slag, a waste byproduct of the smelting process, contains various heavy metals (including copper, lead, zinc, arsenic, etc.). There is a significant concern about the leaching of these heavy metals into the environment, contaminating soil and water. Statement 2 is correct.
– While carbon monoxide (CO) is a toxic gas produced from incomplete combustion processes which might occur in some parts of smelting, it is not typically highlighted as the primary or most widespread lethal air pollution concern from large-scale copper smelting operations compared to SO2. Statement 1 is less likely to be a major *defining* concern.
Other environmental concerns related to copper smelting include particulate matter emissions, arsenic emissions (depending on ore composition), and solid waste disposal (slag). Modern smelting facilities employ technologies like sulfuric acid plants to capture SO2 and convert it into sulfuric acid, mitigating air pollution, but environmental risks remain, particularly from older plants and slag disposal.

17. Which of the following are the reasons/factors for exposure to benzene

Which of the following are the reasons/factors for exposure to benzene pollution ?

  • 1. Automobile exhaust
  • 2. Tobacco smoke
  • 3. Wood burning
  • 4. Using varnished wooden furniture
  • 5. Using products made of polyurethane

Select the correct answer using the code given below :

1, 2 and 3 only
2 and 4 only
1, 3 and 4 only
1, 2, 3, 4 and 5
This question was previously asked in
UPSC IAS – 2020
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Benzene is a volatile organic compound (VOC) and a known carcinogen. All the listed factors contribute to benzene pollution exposure. Automobile exhaust (1) contains benzene from incomplete combustion of fuel. Tobacco smoke (2) is a major source of indoor benzene exposure. Wood burning (3) is another combustion source releasing benzene. Using varnished wooden furniture (4) and products made of polyurethane (5) can off-gas benzene and other VOCs as they may contain solvents or release byproducts containing benzene over time, especially in indoor environments.
Exposure to benzene pollution can occur through combustion sources (vehicles, smoking, burning) and off-gassing from various materials and products (solvents, paints, finishes).
Benzene is also found in crude oil and is used in the manufacture of plastics, resins, synthetic fibers, dyes, detergents, and pesticides. Industrial emissions and hazardous waste sites are other sources. Indoor sources like attached garages (from vehicles), stored fuels, glues, adhesives, paints, and cleaning products also contribute to benzene levels. Given the wide range of sources, it is plausible that all the listed factors contribute to human exposure to benzene.

18. Consider the following statements: 1. Coal ash contains arsenic, lea

Consider the following statements:

  • 1. Coal ash contains arsenic, lead and mercury.
  • 2. Coal-fired power plants release sulphur dioxide and oxides of nitrogen into the environment.
  • 3. High ash content is observed in Indian coal.

Which of the statements given above is/are correct?

1 only
2 and 3 only
3 only
1, 2 and 3
This question was previously asked in
UPSC IAS – 2020
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Statement 1 is correct: Coal ash (fly ash and bottom ash), a residue from burning coal, contains various heavy metals and toxic substances, including arsenic, lead, mercury, chromium, cadmium, and selenium.
Statement 2 is correct: Coal-fired power plants are major sources of air pollution. The combustion process releases sulphur dioxide (SO2) and oxides of nitrogen (NOx) into the atmosphere, which are precursors to acid rain and contribute to respiratory problems.
Statement 3 is correct: Indian coal is known for having a relatively high ash content compared to coal found in many other parts of the world. This high ash content poses challenges for power plants in terms of handling and disposal of large volumes of ash and also affects the efficiency of combustion.
Coal combustion produces significant environmental pollutants, including toxic ash containing heavy metals and gaseous emissions like SO2 and NOx. Indian coal is characterized by high ash content.
The disposal of coal ash is a major environmental challenge. Efforts are being made to promote the utilization of fly ash in various applications like cement manufacturing, brick making, and road construction to minimize disposal impacts.

19. In India, ‘extended producer responsibility’ was introduced as an impo

In India, ‘extended producer responsibility’ was introduced as an important feature in which of the following?

The Bio-medical Waste (Management and Handling) Rules, 1998
The Recycled Plastic (Manufacturing and Usage) Rules, 1999
The e-Waste (Management and Handling) Rules, 2011
The Food Safety and Standard Regulations, 2011
This question was previously asked in
UPSC IAS – 2019
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The correct answer is C. ‘Extended producer responsibility’ was introduced as an important feature in the e-Waste (Management and Handling) Rules, 2011.
Extended Producer Responsibility (EPR) is a policy approach under which producers are given a significant responsibility for the post-consumer stage of their products’ life cycle. In India, the concept of EPR was first formally introduced and elaborated in the e-Waste (Management and Handling) Rules, 2011. These rules made producers responsible for the collection and channelization of e-waste generated from the ‘end-of-life’ of their products. Subsequent rules, like the Plastic Waste Management Rules, 2016, also adopted the EPR principle for plastic waste.
The e-Waste (Management) Rules were further amended in 2016 and 2018, strengthening the provisions for EPR, including setting collection targets for producers. The concept aims to internalize the environmental costs associated with the disposal of goods into the product price, promoting environmentally sound waste management and encouraging product design changes that reduce environmental impact.

20. As per the Solid Waste Management Rules, 2016 in India, which one of t

As per the Solid Waste Management Rules, 2016 in India, which one of the following statements is correct?

Waste generator has to segregate waste into five categories.
The Rules are applicable to notified urban local bodies, notified towns and all industrial townships only.
The Rules provide for exact and elaborate criteria for the identification of sites for landfills and waste processing facilities.
It is mandatory on the part of waste generator that the waste generated in one district cannot be moved to another district.
This question was previously asked in
UPSC IAS – 2019
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Statement C is correct.
Statement A is incorrect. The Solid Waste Management Rules, 2016, mandate waste generators to segregate waste into three streams: wet waste (biodegradable), dry waste (including plastic, paper, metal, wood), and domestic hazardous waste.

Statement B is incorrect. The Rules apply to every urban local body, cantonment board, railway colony, every airport, every port and harbour, every special economic zone, every State and Central Government organisations, and every industrial township, and other entities generating solid waste. Their applicability is much wider than just notified urban local bodies and industrial townships.

Statement C is correct. Schedule I of the Solid Waste Management Rules, 2016, provides detailed and elaborate criteria for the identification of sites for solid waste processing and disposal facilities (like landfills), covering aspects related to environment, land use, and social impact.

Statement D is incorrect. While the rules promote decentralization and managing waste within the urban local body, they do not impose a mandatory prohibition on the movement of waste from one district to another. Movement for regional processing facilities or specific types of waste is permitted subject to regulations and permissions.

The Solid Waste Management Rules, 2016 replaced the Municipal Solid Wastes (Management and Handling) Rules, 2000. Key aspects include source segregation, responsibility of waste generators, role of urban local bodies, waste pickers integration, promotion of composting and bio-methanation, and standards for processing and disposal facilities.
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