Pollution due to its adverse consequences is important part of environment and its syllabus. Previous Year Question (PYQ) papers are invaluable resources for aspirants preparing for competitive exams like the Union Public Service Commission (UPSC) examinations. In this article we present important PYQ on pollution.
PYQ on Pollution
Q- Among the following crops, which one is the most important anthropogenic source of both methane and nitrous oxide ? (2022)
(a) Cotton
(b) Rice
(c) Sugarcane
(d) Wheat
Answer- Option B
EXPLANATION
Rice cultivation with irrigation has been recognized as a significant contributor to anthropogenic methane emissions in global agriculture. Studies suggest that approximately 11% of total anthropogenic methane emissions come from global rice production.
While irrigated rice fields cover only half of the harvested rice area, they contribute to 70% of the rice yield. Therefore, among the listed crops, rice stands out as the primary anthropogenic source of both methane and nitrous oxide emissions.
Q- With reference to polyethylene terephthalate, the use of which is so widespread in our daily lives, consider the following statements: (2022)
- Its fibres can be blended with wool and cotton fibres to reinforce their properties.
- Containers made of it can be used to store any alcoholic beverage.
- Bottles made of it can be recycled into other products.
- Articles made of it can be easily disposed of by incineration without causing greenhouse gas emissions.
Which of the statements given above are correct?
(a) 1 and 3
(b) 2 and 4
(c) 1 and 4
(d) 2 and 3
Answer- Option A
EXPLANATION
Statement 1: Correct. PET (polyethylene terephthalate) fibres are known for their high resistance to deformation, making them ideal for imparting excellent wrinkle resistance in fabrics. These fibres are commonly blended with other materials such as rayon, wool, and cotton to enhance fabric durability and recovery from wrinkling.
Statement 2: Incorrect. The Maharashtra government has indeed announced a ban on the sale of alcohol in PET bottles starting April 1. However, the assertion regarding plastic packaging being dangerous to human health is not directly related to PET. While PET is widely used in carbonated beverage bottles and food jars processed at low temperatures, its low softening temperature restricts its suitability for hot food containers.
Statement 3: Correct. Polyethylene terephthalate is indeed the most commonly recycled plastic. PET bottles and containers are frequently recycled by melting them down and converting them into fibres for various applications such as fibrefill or carpets.
Statement 4: Incorrect. Polyethylene terephthalate, like other plastics, is generally considered inert. However, some additives used in plastic manufacturing, such as bisphenol-A, may leach into the environment over time. Additionally, high-temperature decomposition of plastics can produce hydrocarbon gases. Nonetheless, the statement incorrectly attributes these characteristics specifically to polyethylene, rather than plastics in general.
Q- Which one of the following best describes the term “greenwashing”? (2022)
(a) Conveying a false impression that a company’s products are eco-friendly and environmentally sound
(b) Non-inclusion of ecological/ environmental costs in the Annual Financial Statements of a country
(c) Ignoring the consequences disastrous ecological while infrastructure development undertaking
(d) Making mandatory provisions for environmental costs in a government project/programme
Answer- Option A
EXPLANATION
Greenwashing refers to the deceptive practice of misrepresenting a company’s products as being environmentally friendly or sustainable. It involves conveying false or misleading information to consumers about the environmental benefits of a product. Additionally, greenwashing may occur when a company downplays its involvement in environmentally harmful practices by highlighting the sustainable aspects of its products. This deceptive tactic often involves making vague claims without providing concrete data or scientific evidence to support them.
Q- Consider the following: (2022)
- Carbon monoxide
- Nitrogen oxide
- Ozone
- Sulphur dioxide
Excess of which of the above in the environment is/are cause(s) of acid rain?
(a) 1, 2 and 3
(b) 2 and 4 only
(c) 4 only
(d) 1, 3 and 4
Answer- Option B
EXPLANATION
Pollutants like sulfur dioxide and nitrogen oxide, emitted from the combustion of coal and petroleum products, react with moisture in the atmosphere and rainwater to form sulfuric acid and nitric acid respectively. This resultant mixture, known as acid rain, is detrimental to soil, water, and the growth of crops and aquatic life in rivers, streams, canals, and ponds. Acid rain also inhibits plant growth and corrodes buildings constructed from marble and stone, as well as metal statues. Furthermore, it can lead to respiratory issues such as asthma, bronchitis, and emphysema.
Q- Magnetite particles, suspected to cause neurodegenerative problems are generated as environmental pollutants from which of the following? (2021)
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
(a) 1, 2, 3 and 5only
(b) 1, 2 and 4 only
(c) 3, 4 and 5 only
(d) 1, 2, 3, 4 and 5
Answer- Option D
EXPLANATION
Magnetite particles have been identified as potential pollutants that can contribute to neurodegenerative issues, including the early onset of Alzheimer’s disease, by penetrating and damaging the blood-brain barrier.
Option 1: Correct. The automotive industry utilizes ceramic or ferrite magnets in various safety features, such as Anti-lock Braking Systems (ABS), which can generate magnetic particles.
Option 2: Correct. Engines in motor vehicles incorporate high-powered magnets, resulting in the generation of magnetic flux and particles.
Option 3: Correct. Microwaves employ magnetic stirrers that have the potential to produce magnetic particles.
Option 4: Correct. Power plants emit metal content, including magnetite fine particles, through ash discharge, particularly from the combustion of coal.
Option 5: Correct. Telephone lines emit low-frequency electromagnetic fields, which can serve as a potential source of magnetite particles.
Q- Why is there a concern about copper smelting plants? (2021)
91. They may release lethal quantities of carbon monoxide into the environment
2. The copper slag can cause the leaching of some heavy metals into the environment
3. They may release sulphur dioxide as a pollutant
Select the correct answer using the code given below
(a) 1 and 2 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3
Answer- Option B
EXPLANATION
Statement 1: Incorrect. During the copper smelting process, carbon (C) reacts with oxygen (O2) in the air to form carbon monoxide (CO), which then interacts with the ore, removing one of its oxygen atoms and producing carbon dioxide (CO2). This process does not result in the release of lethal quantities of carbon monoxide into the environment.
Statement 2: Correct. Copper smelters release significant amounts of toxic pollutants such as lead, arsenic, and selenium. These heavy metals, along with particulate matter, contaminate the environment in areas downwind and downstream from the smelters.
Statement 3: Correct. Copper smelters represent the primary source of sulfur oxides (SOx) and trace elements emissions. Suspended particles from smelting activities can contribute to pollution within a range of 2-3 kilometers, while sulfur dioxide (SO2) emissions can spread over distances of up to 15 kilometers.
Q- With reference to furnace oil, consider the following statements: (2021)
1. It is a product of oil refineries
2. Some industries use it to generate power
3. Its use causes sulphur emissions into the environment
Which of the statements given above are correct?
(a) 1 and 2 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3
Answer- Option D
EXPLANATION
Statement 1: Correct. Furnace oil is a dense, dark residual fuel produced by blending the heavier components of crude oil. It is a byproduct of oil refineries.
Statement 2: Correct. Furnace oil serves various purposes, including heating homes, fueling trucks, powering furnaces, generating steam for industrial applications, and producing electrical energy. It is derived from burnable liquids extracted from crude oil and is known by various names such as kerosene, home heating oil, diesel fuel, or coal oil.
Statement 3: Correct. Sulfur is a natural constituent found in crude oil, present in gasoline and diesel unless removed. Furnace oil typically contains a high sulfur content, which contributes to emissions when it is burned.
Q- Which of the following are the reasons/factors for exposure to benzene pollution? (2020)
- Automobile exhaust
- Tobacco smoke
- Wood burning
- Using varnished wooden furniture
- Using products made of polyurethane
Select the correct answer using the code given below:
(a) 1, 2 and 3 only
(b) 2 and 4 only
(c) 1, 3 and 4 only
(d) 1, 2, 3, 4 and 5
Answer- Option A
EXPLANATION
Benzene is a chemical compound that exists as a colorless or light yellow liquid at room temperature, exhibiting limited solubility in water and a tendency to float on its surface. Highly flammable in nature, benzene is produced through natural processes as well as human activities, often present in crude oils and generated as a by-product during oil-refining processes. Notably, benzene is classified as a known human carcinogen, associated with an elevated risk of developing various types of cancers such as lymphatic and hematopoietic cancers, acute myelogenous leukemia, and chronic lymphocytic leukemia.
Its primary usage involves serving as a raw material in the production of various chemicals essential for manufacturing plastics, resins, nylon, and synthetic fibers. Additionally, benzene finds applications in the manufacturing of rubber, lubricants, dyes, detergents, pharmaceuticals, and pesticides, along with being utilized in paints, adhesives, and furniture wax.
Exposure to benzene results in its rapid degradation in the upper atmosphere, with a small proportion being removed by rain and potentially contaminating surface waters and soil due to its solubility in water. Chronic exposure to benzene can lead to the suppression of bone marrow function, resulting in aplastic anemia. Furthermore, benzene is a by-product of tobacco combustion in cigarettes and is also present in wood smoke and automobile exhaust emissions.
Q- In rural road construction, the use of which of the following is preferred for ensuring environmental sustainability or to reduce carbon footprint? (2020)
- Copper slag
- Cold mix asphalt technology
- Geotextiles
- Hot mix asphalt technology
- Portland cement
Select the correct answer using the code given below:
(a) 1, 2 and 3 only
(b) 2, 3 and 4 only
(c) 4 and 5 only
(d) 1 and 5 only
Answer- Option A
EXPLANATION
Using copper slag in cement and concrete offers both environmental and economic advantages to industries involved, especially in regions where significant quantities of copper slag are generated. Therefore, statement 1 is accurate. Cold asphalt mix production requires minimal equipment investment, making it economically viable and environmentally friendly due to its lack of harmful emissions or odors.
Cold asphalt mixes are suitable for initial construction and for recycling asphalt pavements. Thus, statement 2 is correct. Geotextiles play a crucial role in road construction, particularly in enhancing soil structure, filling gaps, and preventing soil erosion while facilitating water drainage. Therefore, statement 3 is accurate. However, statements 4 and 5 are incorrect, as hot asphalt mix and Portland cement are major contributors to CO2 emissions, unlike cold asphalt mix.
Q- Which one of the following statements best describes the term ‘Social Cost of Carbon’? It is a measure, in monetary value, of the (2020)
(a) long-term damage done by a tonne of CO2, emissions in a given year
(b) requirement of fossil fuels for a country to provide goods and services to its citizens, based on the burning of those fuels
(c) efforts put in by a climate refugee to adapt to live in a new place
(d) contribution of an individual person to the carbon footprint on the planet Earth
Answer- Option A
EXPLANATION
The social cost of carbon (SCC) represents the economic impact, quantified in monetary terms, of emitting one additional ton of greenhouse gases into the atmosphere. Therefore, the accurate statement is the enduring harm caused by the emission of one ton of CO2 in a particular year.
Q- In the context of which of the following do some scientists suggest the use of cirrus cloud thinning technique and the injection of sulphate aerosol into the stratosphere? (2019)
(a) Creating artificial rains in some regions
(b) Reducing the frequency and intensity of tropical cyclones
(c) Reducing the adverse effects of solar wind on the Earth
(d) Reducing the global warming
Answer- Option D
EXPLANATION
Cirrus clouds, situated approximately 10 km above the Earth’s surface, have the potential to trap heat. By reducing their thickness, it is possible to cool down the Earth’s system. This thinning process involves introducing ice nuclei, such as dust particles, into areas where cirrus clouds develop. This action leads to the enlargement of ice crystals and a decrease in the optical depth of the cirrus clouds. As a result, more heat can escape into space, ultimately cooling the planet. Employing stratospheric aerosol injection methods could effectively mitigate the rising temperatures associated with climate change.
Q- Why is there a great concern about the ‘microbeads’ that are released into the environment? (2019)
(a) They are considered harmful to marine ecosystems
(b) They are considered to cause skin cancer in children.
(c) They are small enough to be absorbed by crop plants in irrigated fields.
(d) They are often found to be used as food adulterants.
Answer- Option A
EXPLANATION
Microbeads are tiny plastic particles, typically less than one millimeter in size, primarily composed of polyethylene but can also consist of other petrochemical plastics like polypropylene and polystyrene. They find common usage in exfoliating personal care items, toothpastes, and biomedical research. However, their presence in water systems can lead to plastic particle pollution, posing environmental risks to aquatic life in both freshwater and marine environments.
Q- Which of the following statements are correct about the deposits of ‘methane hydrate’? (2019)
- Global warming might trigger the release of methane gas from these deposits
- Large deposits of ‘methane hydrate’ are found in Arctic Tundra and under the seafloor
- Methane in the atmosphere oxidizes to carbon dioxide after a decade or two
Select the correct answer using the code given below.
(a) 1 and 2 only
(b) 2 and 3 only
(c)1 and 3 only
(d) 1, 2 and 3
Answer- Option D
EXPLANATION
A considerable amount of methane is stored within the sediment layers beneath the ocean floor, where it becomes trapped in a frozen state known as methane hydrate. This natural ice-like substance forms under specific conditions of temperature and pressure within subsurface deposits. These conditions are typically found in four Earth environments: below Arctic permafrost, along continental margins, in deep-water sediments of inland lakes and seas, and under Antarctic ice.
When the sea floor and water temperatures rise, methane hydrates can destabilize and release methane gas. Microorganisms in the vicinity then convert this methane into carbon dioxide, a greenhouse gas, which contributes to climate change. Due to its relatively short lifespan in the atmosphere, efforts are being made to curb methane emissions as part of broader initiatives to mitigate the greenhouse effect.
Q- Consider the following: (2019)
- Carbon monoxide
- Methane
- Ozone
- Sulphur dioxide
Which of the above are released into the atmosphere due to the burning of crop/biomass residue?
(a) 1 and 2 only
(b) 2, 3 and 4 only
(c) 1 and 4 only
(d) 1, 2, 3 and 4
Answer- Option D
EXPLANATION
The burning of agricultural crop or biomass residue releases greenhouse gases, air pollutants, particulate matter, and smoke into the atmosphere, posing risks to human health. It is a cost-effective and convenient method for disposing of leftover crop residues after harvest, as well as for land clearing and pest control purposes. This practice is widespread globally.
The combustion of these residues results in the emission of various gases and particles, including sulphur dioxide (SO2), oxides of nitrogen (NOx), carbon dioxide (CO2), carbon monoxide (CO), black carbon (BC), organic carbon (OC), methane (CH4), volatile organic compounds (VOC), non-methane hydrocarbons (NMHCs), ozone (O3), and aerosols. These emissions have significant impacts on the global atmospheric climate. Therefore, all of the provided statements are accurate.
Q- Consider the following statements: (2019)
- Agricultural soils release nitrogen oxides into the environment
- Cattle release ammonia into the environment
- The poultry industry releases reactive nitrogen compounds into the environment
Which of the statements given above is/ are correct?
(a) 1 and 3 only
(b) 2 and 3 only
(c) 2 only
(d) 1, 2 and 3
Answer- Option D
EXPLANATION
The first-ever quantitative assessment of nitrogen pollution in India, known as the Indian Nitrogen Assessment, highlights nitrogen particles as the predominant component of PM 2.5, a category of pollutants closely associated with respiratory and cardiovascular diseases. Additionally, the assessment provides various insights into nitrogen-related data in India. Agricultural soils were identified as the primary source, contributing to over 70% of N2O emissions in 2010, followed by wastewater (12%) and residential and commercial activities (6%), affirming statement 1. Cattle contribute significantly to ammonia production, accounting for 80% of it, despite their stable population growth rate of 1%, supporting statement 2. Conversely, the poultry industry, experiencing a higher annual growth rate of 6%, recorded the excretion of 0.415 tonnes of reactive nitrogen compounds in 2016, confirming statement 3.
Q- In the context of solving pollution problems, which is/are the advantage/advantages of bioremediation techniques? (2017)
- It is a technique of cleaning up pollution by enhancing the same biodegradation process that occurs in nature
- Any contaminant with heavy metals such as cadmium and lead can be readily and completely treated by bioremediation using microorganisms
- Genetic engineering can be used to create microorganisms specifically designed for bioremediation
Select the correct answer using the codes given below:
(a) 1 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2, and 3
Answer- Option C
EXPLANATION
Bioremediation involves employing naturally existing organisms to convert hazardous substances into less harmful or non-toxic forms, constituting a treatment method for degrading pollutants using microorganisms found in soil, water, sludge, and solids. It enhances the natural biodegradation process to mitigate pollution, rendering statement 1 accurate.
However, not all contaminants are susceptible to bioremediation via microorganisms, as certain substances like heavy metals such as cadmium and lead resist absorption or capture by these organisms, indicating statement 2 is inaccurate. Bioremediation primarily relies on bacteria and fungi to decompose environmental pollutants into less harmful forms, and genetic engineering may be utilized to tailor microorganisms specifically for this purpose, confirming statement 3 as true.
Q- In the context of mitigating the impending global warming due to anthropogenic emissions of carbon dioxide, which of the following can be the potential sites for carbon sequestration? (2017)
- Abandoned and uneconomic coal seams
- Depleted oil and gas reservoirs
- Subterranean deep saline formalities
Select the correct answer using the codes given below:
(a) 1 and 2 only
(b) 3 only
(c) 1 and 3 only
(d) 1, 2 and 3
Answer- Option D
EXPLANATION
Carbon sequestration is the process of capturing and storing atmospheric carbon dioxide to reduce its presence in the atmosphere. This method has several applications: Firstly, abandoned and economically unviable coal seams can serve as storage sites for CO2, as the molecules bind to the coal’s surface, validating Statement 1.
CO2 is utilized as a recovery tool in declining oil fields by injecting it to enhance oil recovery, confirming Statement 2. Forests act as natural carbon sinks, with trees effectively sequestering carbon, and wetland restoration contributes significantly to carbon storage, conserving a considerable portion of global soil carbon, thereby supporting Statement 3.
Q- In the cities of our country, which among the following atmospheric gases are normally considered in calculating the value of Air Quality Index? (2016)
- Carbon dioxide
- Carbon monoxide
- Nitrogen dioxide
- Sulfur dioxide
- Methane
Select the correct answer using the code given below.
(a) 1, 2 and 3 only
(b) 2, 3 and 4 only
(c) 1, 4 and 5 only
(d) 1, 2, 3, 4 and 5
Answer- Option B
EXPLANATION
The Air Quality Index (AQI) serves as a metric for assessing the condition of the air. When the AQI falls below 50, it indicates that individuals are inhaling clean and fresh air. The National Air Quality Index (AQI) was introduced in New Delhi in September 2014 as part of the Swachh Bharat Abhiyan initiative. Comprising 8 pollutants, namely PM10, PM2.5, Ozone (O3), Sulphur dioxide (SO2), Nitrogen dioxide (NO2), Carbon monoxide (CO), Lead (Pb), and Ammonia (NH3), the AQI does not encompass measurements for carbon dioxide and methane.
Q- Brominated flame retardants are used in many household products like mattresses and upholstery. Why is there some concern about their use? (2014)
- They are highly resistant to degradation in the environment
- They are able to accumulate in humans and animals
Select the correct answer using the code given below.
(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2
Answer- Option C
EXPLANATION
High concentrations of certain brominated flame retardants can have detrimental effects on wildlife, as they do not readily degrade in the environment. Therefore, Statement 1 is accurate.
Additionally, there is apprehension that these elevated levels could lead to adverse effects in vulnerable human populations, including young children, indigenous communities, and consumers of fish. These chemicals have the potential to accumulate in both humans and animals, contributing to various diseases. Hence, Statement 2 is also valid.
Q- In India, the problem of soil erosion is associated with which of the following? (2014)
- Terrace cultivation
- Deforestation
- Tropical climate
Select the correct answer using the code given below.
(a)1 and 2 only
(b) 2 only
(c) 1 and 3 only
(d) 1, 2 and 3
Answer- Option B
EXPLANATION
Soil erosion refers to the process of losing the uppermost fertile layer of soil due to the action of wind or water. This phenomenon can be caused by various factors, including over-grazing, deforestation, natural forces like wind, water, or glaciers, as well as human activities such as mining and industrial operations.
Factors such as steep slopes, heavy rainfall, and improper agricultural practices like over-irrigation or shifting cultivation can exacerbate soil erosion. To mitigate soil erosion, methods like terrace farming and contour plowing are employed to help control the loss of soil.
Q- The scientific view is that the increase in global temperature should not exceed 2 C above pre-industrial level. If the global temperature increases beyond 3 C above the pre industrial level, what can be its possible impact/ impacts on the world? (2014)
- Terrestrial biosphere tends toward a net carbon source
- Widespread coral mortality will occur
- All the global wetlands will permanently disappear
- Cultivation of cereals will not be possible anywhere in the world
Select the correct answer using the code given below.
(a) 1 only
(b) 1 and 2 only
(c) 2, 3, and 4 only
(d) 1, 2, 3 and 4
Answer- Option B
EXPLANATION
The terrestrial biosphere plays a crucial role in regulating atmospheric composition and climate by absorbing and releasing greenhouse gases like carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). It also controls the exchange of energy, water, and aerosols between the Earth’s surface and the atmosphere. While carbon is primarily exchanged with the atmosphere, small amounts also enter the oceans as dissolved organic carbon. If global temperatures rise beyond 3°C above pre-industrial levels, the terrestrial biosphere may become a net carbon source, potentially altering ecosystems like taiga and temperate forests from carbon sinks to sources.
Corals, belonging to the group Cnidaria, form diverse marine ecosystems known as coral reefs, housing thousands of species including fish, cnidarians, mollusks, and crustaceans. However, as temperatures increase, coral bleaching events become more frequent, leading to widespread coral mortality. While temperate regions may fare better due to their ability to withstand seasonal changes, sustained warming could threaten coral survival. Nonetheless, temperate zones still provide suitable conditions for cereal cultivation, given their warm and moist weather during cereal growth stages.
Q- Which of the following can be found as pollutants in the drinking water in some parts of India? (2013)
- Arsenic
- Sorbitol
- Fluoride
- Formaldehyde
- Uranium
Select the correct answer using the codes given below.
(a) 1 and 3 only
(b) 2, 4 and 5 only
(c) 1, 3 and 5 only
(d) 1, 2, 3, 4 and 5
Answer- Option C
EXPLANATION
Arsenic contaminates groundwater primarily through industrial and mining discharges, as well as from fly ash ponds of thermal power plants. It is highly toxic and chronic exposure may lead to ailments such as black foot disease, diarrhoea, lung cancer, and skin cancer.
Excessive fluoride in drinking water can result in various health issues, including knock-knee syndrome, fluorosis, neuromuscular disorders, gastrointestinal problems, and dental deformities.
According to a report conducted by Duke University in collaboration with the Central Ground Water Board and State Ground Water departments, several states in India, including Andhra Pradesh, Chhattisgarh, Gujarat, Haryana, Himachal Pradesh, Jharkhand, Karnataka, Maharashtra, Odisha, Punjab, Rajasthan, Tamil Nadu, Telangana, Uttar Pradesh, West Bengal, and Jammu & Kashmir, have localized occurrences of high Uranium concentrations.
Q- Acid rain is caused by the pollution of environment by (2013)
(a) carbon dioxide and nitrogen
(b) carbon monoxide and carbon dioxide
(c) ozone and carbon dioxide
(d) nitrous oxide and sulphur dioxide
Answer- Option D
EXPLANATION
Acid rain is defined as any form of precipitation, such as rain, snow, or fog, that contains elevated levels of hydrogen ions, resulting in a low pH level below 5.6. Acid rain is primarily caused by acidic oxides of sulfur and nitrogen, which are released into the atmosphere through human activities like burning fossil fuels and volcanic eruptions. Once in the atmosphere, these oxides undergo oxidation and react with water, leading to the formation of sulfur dioxide and nitrogen oxides, which are major contributors to the phenomenon of acid rain.
Also read about UPSC PYQ on Environmental Laws and Environmental Convention