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Topics / Environment

Pollution

Asked 27 times in UPSC Prelims · first asked 2000 · last asked 2025

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Consider the following statements: Statement I: Activated carbon is a good and an attractive tool to remove pollutants from effluent streams and to remediate contaminants from various industries. Statement II: Activated carbon exhibits a large surface area and a strong potential for adsorbing heavy metals. Statement III: Activated carbon can be easily synthesized from environmental wastes with high carbon content. Which one of the following is correct in respect of the above statements?

2025Environment
ABoth Statement II and Statement III are correct and both of them explain Statement I
BBoth Statement II and Statement III are correct but only one of them explains Statement I
COnly one of the Statements II and III is correct and that explains Statement I
DNeither Statement II nor Statement III is correct

Explanation

Activated carbon is an effective tool for removing pollutants due to its large surface area, which provides ample sites for adsorption of heavy metals. It can be synthesized from environmental wastes with high carbon content, making it a sustainable option for remediation in various industries. Both these aspects align with the effectiveness of activated carbon in treating effluent streams and contaminants, as mentioned in Statement I.

With reference to perfluoroalkyl and polyfluoroalkyl substances (PFAS) that are used in making many consumer products, consider the following statements: 1. PFAS are found to be widespread in drinking water, food and food packaging materials. 2. PFAS are not easily degraded in the environment. 3. Persistent exposure to PFAS can lead to bioaccumulation in animal bodies. Which of the statements given above are correct?

2024Environment
A1 and 2 only
B2 and 3 only
C1 and 3 only
D1, 2 and 3

Explanation

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are indeed widespread in drinking water, food, and food packaging materials due to their extensive use in consumer products. These substances are known for their environmental persistence, as they are not easily degraded, leading to long-term contamination. Moreover, persistent exposure to PFAS can result in bioaccumulation in animal bodies, posing health risks to both wildlife and humans.

Consider the following statements: Statement-I: Many chewing gums found in the market are considered a source of environmental pollution. Statement-II: Many chewing gums contain plastic as gum base. Which one of the following is correct in respect of the above statements?

2024Environment
ABoth Statement-I and Statement-II are correct and Statement-II explains Statement-I
BBoth Statement-I and Statement-II are correct, but Statement-II does not explain Statement-I
CStatement-I is correct, but Statement-II is incorrect
DStatement-I is incorrect, but Statement-II is correct

Explanation

Many chewing gums in the market contain plastic as a gum base, making them a potential source of environmental pollution. This is because plastic is non-biodegradable and can persist in the environment for a long time, contributing to pollution.

According to the Environmental Protection Agency (EPA), which one of the following is the largest source of sulphur dioxide emissions?

2024Environment
ALocomotives using fossil fuels
BShips using fossil fuels
CExtraction of metals from ores
DPower plants using fossil fuels

Explanation

Power plants that use fossil fuels are the largest source of sulphur dioxide emissions according to the Environmental Protection Agency (EPA). When fossil fuels like coal or oil are burned in power plants, sulphur dioxide is released into the atmosphere, contributing significantly to air pollution. This emission can lead to acid rain, respiratory issues, and other environmental and health problems.

Consider the following statements regarding mercury pollution: 1. Gold mining activity is a source of mercury pollution in the world. 2. Coal-based thermal power plants cause mercury pollution. 3. There is no known safe level of exposure to mercury. How many of the above statements are correct?

2023Environment
AOnly one
BOnly two
CAll three
D

Explanation

Gold mining activities release mercury into the environment due to the use of mercury in the extraction process. Coal-based thermal power plants emit mercury into the air through combustion processes, contributing to mercury pollution. It is important to note that there is no known safe level of exposure to mercury, as even low levels can have harmful effects on human health and the environment.

Consider the following: 1. Carbon monoxide 2. Nitrogen oxide 3. Ozone 4. Sulphur dioxide. Excess of which of the above in the environment is/are cause(s) of acid rain?

2022Environment
A1, 2 and 3
B2 and 4 only
C4 only
D1, 3 and 4

Explanation

Nitrogen oxide and sulphur dioxide are the primary pollutants responsible for causing acid rain. When these gases react with water vapor in the atmosphere, they form nitric acid and sulfuric acid, which then fall to the ground as acid rain.

In the context of WHO Air Quality Guidelines, consider the following statements: 1. The 24-hour mean of PM2.5 should not exceed 15 μg/m³ and annual mean of PM2.5 should not exceed 5 μg/m³. 2. In a year the highest levels of ozone pollution occur during the periods of inclement weather. 3. PM10 can penetrate the lung barrier and enter the bloodstream. 4. Excessive ozone in the air can trigger asthma. Which of the statements given above are correct?

2022Environment
A1, 3 and 4
B1 and 4 only
C2, 3 and 4
D1 and 2 only

Explanation

PM2.5 refers to particulate matter with a diameter of 2.5 micrometers or less, and the WHO guidelines recommend that the 24-hour mean should not exceed 15 μg/m³ and the annual mean should not exceed 5 μg/m³ to maintain air quality. Excessive ozone in the air can indeed trigger asthma, making statements 1 and 4 correct.

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.

2021Environment
A1 and 2 only
B2 and 3 only
C1 and 3 only
D1 2 and 3

Explanation

Copper smelting plants are a concern due to the potential leaching of heavy metals like copper slag into the environment. Additionally, these plants can release sulphur dioxide as a pollutant, contributing to air pollution.

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?

2021Environment
A1 and 2 only
B2 and 3 only
C1 and 3 only
D1 2 and 3

Explanation

Furnace oil is a product of oil refineries used by industries to generate power. Its combustion releases sulphur emissions into the environment, contributing to air pollution.

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

2021Environment
A1 2 3 and 5 only
B1 2 and 4 only
C3 4 and 5 only
D1 2 3 4 and 5

Explanation

Magnetite particles, which are suspected to cause neurodegenerative problems, are generated as environmental pollutants from the brakes and engines of motor vehicles, microwave stoves within homes, power plants, and telephone lines. These particles are a type of air pollution that can have adverse health effects on humans.

'Triclosan', considered harmful when exposed to high levels for a long time, is most likely present in which of the following?

2021Environment
AFood preservatives
BFruit-ripening substances
CReused plastic containers
DToiletries

Explanation

Triclosan is a common ingredient in toiletries such as soaps, toothpaste, and hand sanitizers due to its antimicrobial properties. Prolonged exposure to high levels of triclosan in toiletries has been associated with potential harmful effects on health and the environment.

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:

2020Environment
A1, 2 and 3 only
B2 and 4 only
C1, 3 and 4 only
D1, 2, 3, 4 and 5

Explanation

Benzene pollution exposure can occur due to various sources such as automobile exhaust, tobacco smoke, wood burning, using varnished wooden furniture, and products made of polyurethane. These factors contribute to the presence of benzene in the environment. Benzene and polycyclic aromatic hydrocarbons (PAH) are commonly produced during incomplete combustion of coal, oil, petrol, and wood, as well as in cigarette smoke. Additionally, benzene can be found in materials like particleboard furniture, plywood, fibreglass, flooring adhesives, paints, and wood panelling.

Why is there a great concern about the microbeads that are released into environment?

2019Environment
AThey are considered harmful to marine ecosystem
BThey are considered to cause skin cancer in children
CThey are small enough to be absorbed by crop plants in irrigated fields
DThey are often found to be used as food adulterants

Explanation

The Bureau of Indian Standards (BIS) has labeled microbeads as 'unsafe' for inclusion in cosmetic items. Previously, the National Green Tribunal (NGT) instructed the government to analyze cosmetic products that contain microbeads, following a request to prohibit their use due to their significant harm to marine life and the environment.

Consider the following: 1. Carbon monoxide 2. Methane 3. Ozone 4. Sulphur dioxide Which of the above are released into the atmosphere due to the burning of crop/biomass residue?

2019Environment
A1 and 2 only
B2, 3 and 4 only
C1 and 4 only
D1, 2, 3 and 4

Explanation

When crop or biomass residue is burned, gases like carbon monoxide, methane, ozone, and sulphur dioxide are released into the atmosphere. This contributes to air pollution and affects the environment. It is important to understand and address the impact of biomass burning on greenhouse gas emissions and air quality.

Consider the following statements: 1. Agricultural soils release nitrogen oxides into environment. 2. Cattle release ammonia into environment. 3. Poultry industry releases reactive nitrogen compounds into environment. Which of the statements given above is/are correct?

2019Environment
A1 and 3 only
B2 and 3 only
C2 only
D1, 2 and 3

Explanation

In 2010, agricultural soils in India were responsible for more than 70% of nitrogen oxide emissions. Cattle contributed to 80% of ammonia production. In 2016, the poultry industry released 0.415 tonnes of reactive nitrogen compounds.

Which of the following can be found as pollutants in the drinking water in some parts of India? 1. Arsenic 2. Sorbitol 3. Fluoride 4. Formaldehyde 5. Uranium Select the correct answer using the codes given below:

2018Environment
A1, 3 and 5 only
B2, 4 and 5 only
C1, 2, 3, 4 and 5
D1, 3 and 4 only

Explanation

In certain regions of India, contaminants such as arsenic, fluoride, and uranium can be present in drinking water. The correct answer to the question is option (a), which includes only arsenic, fluoride, and uranium as pollutants found in some parts of India's drinking water.

Consider the following statements: 1. Agricultural soils release nitrogen oxides into environment 2. Cattle release ammonia into environment 3. Poultry industry releases reactive nitrogen compounds into environment Which of the statements given above is/are correct?

2018Environment
A1 and 3 only
B2 and 3 only
C2 only
D1, 2 and 3

Explanation

In this question, we are presented with three statements about the release of nitrogen compounds into the environment. Statement 1 states that agricultural soils release nitrogen oxides, statement 2 mentions that cattle release ammonia, and statement 3 indicates that the poultry industry releases reactive nitrogen compounds. The correct answer is option (d), which means that all three statements are correct. This is because agricultural soils release nitrogen oxides, cattle release ammonia, and the poultry industry releases various nitrogen compounds into the environment.

Biological Oxygen Demand (BOD) is a standard criterion for

2017Environment
AMeasuring oxygen levels in blood
BComputing oxygen levels in forest ecosystems
CPollution assay in aquatic ecosystems
DAssessing oxygen levels in high altitude regions

Explanation

Biological Oxygen Demand (BOD) is a measure of the oxygen needed by bacteria to decompose organic matter in a specific volume of water. It indicates the level of organic material present in the water.

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

2016Environment
A1, 2 and 3 only
B2 and 4 only
C1, 3 and 4 only
D1, 2, 3, 4 and 5

Explanation

Exposure to benzene pollution can occur due to various factors, including automobile exhaust, tobacco smoke, wood burning, using varnished wooden furniture, and using products made of polyurethane. Therefore, all the factors listed in the options can lead to exposure to benzene pollution.

In the cities of our country, which among the following atmospheric gases are normally considered in calculating the value of Air Quality Index? 1. Carbon dioxide 2. Carbon monoxide 3. Nitrogen dioxide 4. Sulfur dioxide 5. Methane Select the correct answer using the code given below.

2016Environment
A1, 2 and 3 only
B2, 3 and 4 only
C1, 4 and 5 only
D1, 2, 3, 4 and 5

Explanation

The Air Quality Index (AQI) in urban areas of our country typically considers certain atmospheric gases to determine air quality. These gases include carbon monoxide, nitrogen dioxide, and sulfur dioxide. The correct answer is option (b), which includes gases 2, 3, and 4. The AQI level is determined based on the concentration of various pollutants like sulfur dioxide, nitrogen dioxide, particulate matter (PM2.5), ammonia, lead, carbon monoxide, and ozone.

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.

2014Environment
A1, 3 and 4 only
B1 and 3 only
C1 and 4 only
D1, 2, 3 and 4

Explanation

The steel industry in India releases several important pollutants, including oxides of sulphur, oxides of nitrogen, carbon monoxide, and carbon dioxide. These pollutants are produced when coke in the steel furnace reacts with iron. The correct answer is option (d), which includes all of the mentioned pollutants.

Which of the following can be found as pollutants in the drinking water in some parts of India? 1. Arsenic 2. Sorbitol 3. Fluoride 4. Formaldehyde 5. Uranium Select the correct answer using the codes given below.

2013Environment
A1 and 3 only
B2, 4 and 5 only
C1, 3 and 5 only
D1, 2, 3, 4 and 5

Explanation

In certain regions of India, drinking water can contain harmful substances such as arsenic, fluoride, and other pollutants.

There is a concern over the increase in harmful algal blooms in the seawaters of India. What could be the causative factors for this phenomenon? 1. Discharge of nutrients from the estuaries. 2. Run-off from the land during the monsoon. 3. Upwelling in the seas. Select the correct answer from the codes given below:

2011Environment
A1 only
B1 and 2 only
C2 and 3 only
D1, 2 and 3

Explanation

The increase in harmful algal blooms in Indian seawaters is influenced by various factors. Nutrient discharge from estuaries provides a favorable environment for algae growth, leading to blooms. During the monsoon, land runoff brings salts that also promote algae growth. Upwelling in the seas brings nutrients to the surface, further facilitating rapid algae multiplication. All these factors contribute to the phenomenon of harmful algal blooms in Indian seawaters.

Consider the following: 1. Carbon dioxide 2. Oxides of Nitrogen 3. Oxides of Sulphur Which of the above is/are the emission/emissions from coal combustion at thermal power plants?

2011Environment
A1 only
B2 and 3 only
C1 and 3 only
D1, 2 and 3

Explanation

When coal is burned at thermal power plants, it releases carbon dioxide, oxides of nitrogen, and oxides of sulfur. This means that all three emissions - CO2, NOx, and SOx - are produced during coal combustion at these facilities.

Pneumoconiosis affects the workers who work mainly in

2005Environment
ATanneries
BCoal mining industry
CDistilleries
DGlass industry

Explanation

Pneumoconiosis is a lung disease that impacts individuals working in coal mining due to inhaling coal dust.

Silicosis is a health hazard to workers in

2002Environment
APottery industry
BTextile industry
CMining industry
DFarming

Explanation

Silicosis is a respiratory condition that occurs when workers inhale fine particles of crystalline silica dust. This health hazard is particularly prevalent in the mining industry.

Most of the explosions in mines occur due to the mixing of

2000Environment
Ahydrogen with oxygen
Boxygen with acetylene
Cmethane with air
Dcarbon dioxide with ethane

Explanation

The majority of mine explosions are caused by the formation of explosive mixtures when methane gas mixes with air inside mines.