Pollution

1. Which of the following are the major contaminants from industries and

Which of the following are the major contaminants from industries and households that cause cultural eutrophication?

Chlorine and aldrin
Mercury and nitrates
Nitrates and phosphates
Phosphates and ammonium
This question was previously asked in
UPSC CISF-AC-EXE – 2024
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The correct answer is C) Nitrates and phosphates.
Cultural eutrophication is the process of nutrient enrichment of water bodies by human activities. The major contaminants from industries, agriculture, and households that cause this are compounds of nitrogen (like nitrates) and phosphorus (like phosphates). These nutrients promote excessive growth of algae and aquatic plants.
Sources of nitrates include agricultural runoff (fertilizers), sewage, and atmospheric deposition. Sources of phosphates include detergents (historically), sewage, industrial waste, and agricultural runoff. High concentrations of these nutrients disrupt aquatic ecosystems by leading to algal blooms, oxygen depletion (hypoxia) upon decomposition of dead algae, and loss of biodiversity.

2. Consider the following statements : It was alleged that the river b

Consider the following statements :

  • It was alleged that the river became dead after its mouth was closed restricting its free flow in 1950. The entire river bed was converted into a dumping ground for garbage and solid and liquid waste. The National Green Tribunal has recently directed the State Government to revive the dead river by earmarking dedicated fund for the purpose.

Identify the river :

Vamsadhara river
Sukapaika river
Musi river
Ulhas river
This question was previously asked in
UPSC CISF-AC-EXE – 2023
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The description matches the case of the Sukapaika river in Odisha. Sukapaika is a distributary of the Mahanadi river.
In 1950, the mouth of the Sukapaika river was closed to prevent flooding in the region, which subsequently choked the river’s flow, leading to its conversion into a dumping ground and its eventual ‘death’.
Following petitions and environmental concerns, the National Green Tribunal (NGT) directed the Odisha government to take steps to revive the Sukapaika river, including clearing obstructions and ensuring water flow. The state government has since initiated a restoration project.

3. Recently, thousands of birds were killed in the shoreline of which one

Recently, thousands of birds were killed in the shoreline of which one of the following lakes of India by the infection of avian botulism, a deadly neuro-muscular illness ?

Haflong lake, Assam
Sukhna lake, Chandigarh
Badkhal lake, Haryana
Sambhar lake, Rajasthan
This question was previously asked in
UPSC CISF-AC-EXE – 2020
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In late 2019, thousands of migratory birds died at Sambhar Lake in Rajasthan due to an outbreak of avian botulism.
Avian botulism is a neuro-muscular illness caused by toxins produced by the bacterium *Clostridium botulinum*, typically under warm, stagnant water conditions.
Sambhar Lake is India’s largest inland salt lake and a crucial wetland for migratory birds. The mass death raised significant environmental concerns.

4. Match List-I with List-II and select the correct answer using the code

Match List-I with List-II and select the correct answer using the code given below the Lists :

List-I
(Convention)		 List-II
(Primarily related to)
A. Basel Convention 1. Organic pollutants
B. Rotterdam Convention 2. Mercury
C. Stockholm Convention 3. Hazardous wastes
D. Minamata Convention 4. Pesticides
A-3, B-1, C-4, D-2
A-2, B-4, C-1, D-3
A-3, B-4, C-1, D-2
A-2, B-1, C-4, D-3
This question was previously asked in
UPSC CISF-AC-EXE – 2019
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Let’s match the Conventions with their primary focus:
– Basel Convention: Adopted in 1989, it controls transboundary movements of hazardous wastes and their disposal. Matches with ‘Hazardous wastes’ (3).
– Rotterdam Convention: Adopted in 1998, it established the Prior Informed Consent (PIC) procedure for certain hazardous chemicals and pesticides in international trade. Matches with ‘Pesticides’ (4) and hazardous chemicals.
– Stockholm Convention: Adopted in 2001, it is a global treaty to protect human health and the environment from Persistent Organic Pollutants (POPs). Matches with ‘Organic pollutants’ (specifically POPs) (1).
– Minamata Convention: Adopted in 2013, it is a global treaty to protect human health and the environment from the adverse effects of mercury. Matches with ‘Mercury’ (2).
The correct matching is A-3, B-4, C-1, D-2.
– Basel Convention: Hazardous waste movement.
– Rotterdam Convention: Prior Informed Consent for chemicals/pesticides.
– Stockholm Convention: Persistent Organic Pollutants (POPs).
– Minamata Convention: Mercury pollution.
These conventions are key international environmental agreements aimed at regulating dangerous substances and waste to protect global health and ecosystems. The Rotterdam Convention covers a broad range of hazardous chemicals and pesticides, but ‘Pesticides’ is the most fitting primary focus among the given options for B.

5. Which one of the following is an eco-friendly solvent ?

Which one of the following is an eco-friendly solvent ?

Liquid ammonia
Carbon disulphide
Benzene
Water
This question was previously asked in
UPSC CISF-AC-EXE – 2018
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An eco-friendly or green solvent minimizes environmental impact. Water is considered the most eco-friendly solvent due to its abundance, low cost, non-toxicity, non-flammability, and lack of harmful vapours. Other options are less environmentally friendly: Liquid ammonia is corrosive and toxic. Carbon disulphide is toxic, highly flammable, and volatile. Benzene is a known carcinogen, toxic, and volatile.
Water is widely regarded as the most eco-friendly solvent.
Green chemistry aims to design chemical products and processes that reduce or eliminate the use and generation of hazardous substances. Choosing appropriate solvents is a key aspect of green chemistry.

6. According to the Environmental Protection Agency (EPA), which one of t

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

Locomotives using fossil fuels
Ships using fossil fuels
Extraction of metals from ores
Power plants using fossil fuels
This question was previously asked in
UPSC IAS – 2024
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The correct option is D.
According to the Environmental Protection Agency (EPA) and most environmental agencies globally, the largest source of sulphur dioxide (SO2) emissions is the burning of fossil fuels, particularly coal, by power plants and other industrial facilities. Fossil fuels often contain sulphur, which is converted to SO2 when burned. Power plants, due to the large volume of fuel consumed, are the dominant source.
Other sources like locomotives, ships using fossil fuels, and metal extraction processes also contribute to SO2 emissions, but typically to a lesser extent compared to large power generation facilities. SO2 is a major air pollutant contributing to acid rain and respiratory problems.

7. Consider the following statements: Statement-I : Many chewing gums fou

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 ?

Both Statement-I and Statement-II are correct and Statement-II explains Statement-I
Both Statement-I and Statement-II are correct, but Statement-II does not explain Statement-I
Statement-I is correct, but Statement-II is incorrect
Statement-I is incorrect, but Statement-II is correct
This question was previously asked in
UPSC IAS – 2024
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Statement-I is correct. Discarded chewing gum is a significant source of litter and environmental pollution. It is sticky, difficult to remove from surfaces like pavements, and takes a very long time to degrade. Statement-II is correct. The gum base used in most modern chewing gums is made of synthetic polymers, which are essentially types of plastic (e.g., polyisobutylene, polyvinyl acetate, polyethylene). These synthetic polymers are non-biodegradable or degrade extremely slowly. The fact that chewing gum contains non-biodegradable plastic explains why it persists in the environment when discarded and is considered a pollutant. Therefore, Statement-II provides the reason for Statement-I.
– Chewing gum litter is a persistent environmental problem.
– Modern chewing gum bases are often made of synthetic polymers (plastics).
– Plastic components contribute to the non-biodegradability of discarded gum.
Traditional chewing gums were made from natural latexes like chicle. However, since the mid-20th century, synthetic alternatives have become predominant due to cost and consistency. The plastic nature of the gum base is the primary reason for the environmental concerns associated with its disposal.

8. With reference to perfluoroalkyl and polyfluoroalkyl substances (PFAS)

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?

1 and 2 only
2 and 3 only
1 and 3 only
1, 2 and 3
This question was previously asked in
UPSC IAS – 2024
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All three statements regarding perfluoroalkyl and polyfluoroalkyl substances (PFAS) are correct. PFAS are synthetic chemicals used in a wide range of products, leading to their presence in various environmental media, including drinking water, food, and food packaging. They are known for their strong carbon-fluorine bonds, which make them extremely persistent and resistant to degradation in the environment and biological systems, hence the term “forever chemicals”. Due to their persistence, they can accumulate in the tissues of living organisms, including animals and humans, through repeated exposure, a process known as bioaccumulation.
PFAS are persistent, bioaccumulative, and toxic substances (PBTs). Their widespread use and environmental persistence are major concerns for human health and the environment.
Exposure to PFAS has been linked to various adverse health effects, including immune system effects, hormonal disruption, increased cholesterol levels, and potential links to certain cancers. Regulations and efforts to mitigate PFAS contamination are ongoing globally.

9. “Membrane Bioreactors” are often discussed in the context of which one

“Membrane Bioreactors” are often discussed in the context of which one of the following ?

Assisted reproductive technologies
Drug delivery nanotechnologies
Vaccine production technologies
Wastewater treatment technologies
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UPSC IAS – 2024
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Membrane Bioreactors (MBRs) are a technology used extensively in wastewater treatment. An MBR system combines a biological treatment process (such as activated sludge) with a membrane filtration step. The membranes are used to separate treated water from the activated sludge, effectively replacing the secondary clarifier and tertiary filtration found in conventional wastewater treatment plants. This allows for a higher concentration of biomass in the biological reactor, leading to more efficient treatment and producing high-quality effluent.
MBRs integrate biological treatment with membrane filtration for improved separation and treatment efficiency in wastewater management.
MBRs are particularly useful for treating municipal and industrial wastewater where space is limited, or high effluent quality is required, such as for water reuse applications. They offer advantages like smaller footprint, better effluent quality, and reduced sludge production compared to conventional systems.

10. Consider the following statements regarding mercury pollution : 1. G

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?

Only one
Only two
All three
None
This question was previously asked in
UPSC IAS – 2023
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All three statements regarding mercury pollution are correct. Gold mining, coal-based thermal power plants, and the lack of a known safe exposure level are well-established facts related to mercury pollution and health impacts.
– Artisanal and small-scale gold mining (ASGM) is a major global source of anthropogenic mercury emissions due to the use of mercury to extract gold.
– Combustion of coal in power plants releases mercury that is naturally present in coal.
– According to the World Health Organization (WHO), there is no known safe level of exposure to elemental (metallic) mercury, as it is toxic even at very low concentrations.
Mercury is a persistent, bioaccumulative toxic substance. It can travel long distances in the atmosphere and settle in ecosystems, where it can be converted to highly toxic methylmercury, which bioaccumulates in food chains, particularly in fish. The Minamata Convention on Mercury is an international treaty designed to protect human health and the environment from anthropogenic emissions and releases of mercury and mercury compounds.
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