Selina Concise Solutions for ICSE Class 9 Geography Chapter 16 Pollution

Exercises

I. Short Answer Questions

Question 1. What is environmental pollution ?
Answer: Environmental pollution refers to any unfavourable alteration of our surroundings, wholly or largely as a by product of man’s actions. These changes may affect man and other organisms.
In simple words: It is when we change our environment in a bad way through our activities. This can hurt people, animals, and plants living there.

📝 Teacher's Note: Explain "unfavourable alteration" as "bad changes" like dirty air or water that wasn't there before.

🎯 Exam Tip: Use the keyword "unfavourable alteration" to score full marks in your definition.

Question 2. Give the definition of a pollutant.
Answer: A pollutant is a product released into the biosphere disturbing the normal functioning of ecosystem due to its adverse effect on plants, animals and man.
In simple words: A pollutant is a "bad thing" added to nature that upsets how it works. It usually makes living things sick or causes damage to the environment.

📝 Teacher's Note: Tell students to think of a pollutant as a "disturber" of nature's peace and health.

🎯 Exam Tip: Remember that a substance must cause an "adverse effect" on living things to be scientifically defined as a pollutant.

Question 3. Give the difference between natural and man-made pollutants.
Answer: Natural pollution takes place by increasing the quantity of Carbon dioxide and Nitrogen oxide in the atmosphere but man made pollution is done by using pesticides, chemical fertilizers.
In simple words: Natural pollution comes from nature itself, like volcanoes or extra gases already in the air. Man-made pollution comes from things humans create, like chemicals for farming.

📝 Teacher's Note: Ask students for other examples, like forest fires (natural) vs. factory smoke (man-made) to deepen their understanding.

🎯 Exam Tip: Give at least one specific example for each type, like "Nitrogen oxide" for natural and "pesticides" for man-made.

Question 4. What is air pollution ? Give a source of air pollution.
Answer: Air pollution is the excessive concentration of foreign matter in the air which adversely affects the well-being of human beings, animals, plants and their environment. Air pollution is caused by addition of chemicals, carbon monoxide, sulphur dioxide, hydrogen sulphide by various factories, industrial plants.
In simple words: Air pollution is when too much "junk" gets into the air and makes it unhealthy to breathe. Factories are a big source because they release harmful gases like carbon monoxide.

📝 Teacher's Note: Explain "foreign matter" as things that don't belong in clean air, like smoke and toxic chemical fumes.

🎯 Exam Tip: Listing specific chemical names like "Sulphur dioxide" shows the examiner you have studied the topic thoroughly.

Question 5. Define water pollution.
Answer: Water pollution is caused by contamination of water by alteration in physical, chemical, biological characteristics of water making it unsuitable for designated use in its natural state.
In simple words: Water pollution is when water becomes dirty and unsafe to use for drinking or swimming. This happens when its look, chemical mix, or the tiny germs inside it change for the worse.

📝 Teacher's Note: Use the analogy of a glass of water with mud (physical), salt (chemical), and bacteria (biological) to explain the three characteristics.

🎯 Exam Tip: The keyword here is "unsuitable for designated use"-make sure to include it in your final answer.

Question 6. What is soil pollution ?
Answer: Soil pollution is defined as the change in physical, chemical and biological conditions of the soil through man’s intervention resulting in degradation in quality and productivity of soil.
In simple words: Soil pollution is when we damage the ground through farming chemicals or waste. This makes the soil poor in quality so it can't grow healthy plants or crops anymore.

📝 Teacher's Note: Explain that "productivity" means the soil's ability to grow a high amount of crops for food.

🎯 Exam Tip: Always mention "man's intervention" to show that human activities are the main cause of this soil damage.

Question 7. Why should we avoid soil pollution.
Answer: Soil is the basic need of agriculture. If the soil is polluted, the crops will be harmful for health and quality.
In simple words: We need clean soil to grow our food like fruits and vegetables. If the ground is dirty, the food we eat from it can carry toxins that make us sick.

📝 Teacher's Note: Remind students that toxins in the soil are absorbed by the roots of plants and eventually end up in our bodies.

🎯 Exam Tip: Link soil quality directly to "human health" and "crop quality" to provide a strong reasoning answer.

Question 8. What is radioactive pollution ?
Answer: Radioactive pollution is done by cosmic radiation from space, terrestrial radiation from radio-isotopes from earth’s crust, nuclear fuels in atomic plants, atomic bombs etc.
In simple words: This is a dangerous type of pollution caused by invisible energy rays. It can come from space, special rocks in the ground, or man-made nuclear power and bombs.

📝 Teacher's Note: Explain that unlike smoke, you cannot see or smell radioactive pollution, which makes it very dangerous and hard to detect.

🎯 Exam Tip: Mention "nuclear fuels" and "atomic bombs" as the primary man-made sources of this pollution.

Question 9. What is noise pollution ? What harm does noise pollution do to human beings ?
Answer: Noise pollution is done by extreme noise done by industrial sector, transport, loud speakers etc., which adversely affect human health causing severe headache, migraine, mental disbalance, nervous breakdown, heart diseases.
In simple words: Noise pollution is simply too much loud sound from traffic or machines. It can cause serious health problems like bad headaches and even heart issues.

📝 Teacher's Note: Help students understand that "unwanted sound" is a form of stress that wears down the human body over time.

🎯 Exam Tip: List at least three specific health effects like "migraine," "nervous breakdown," and "heart diseases" to get full marks.

Question 10. Give the difference between biodegradable and non- biodegradable pollutants.
Answer: Biodegradable pollutants are degraded by microbial actions e.g. sewage, garbage etc, but non-biodegradable pollutants are not degraded e.g. glass, plastics etc.
In simple words: Biodegradable things can be broken down naturally by tiny germs. Non-biodegradable things, like plastic bottles, stay in the environment forever because nature cannot "eat" them.

📝 Teacher's Note: Use the "Banana peel vs. Plastic bag" example-nature can break down the peel in weeks, but the bag takes hundreds of years.

🎯 Exam Tip: Use the scientific term "microbial actions" to explain how biodegradable things are broken down.

Question 11. Distinguish between each of the following :
(i) Biodegradable and Non-biodegradable Pollutants
Answer:
Biodegradable Pollutants :
1. These may be degraded "after sometime by biological or microbial actions.
2. These are sewage, domestic garbage of kitchen etc.
Non-biodegradable Pollutants :
1. These are not degraded by any biological or microbial actions.
2. These include plastics, pesticides and radioactive materials.
In simple words: Nature can "digest" biodegradable waste through biological processes, but it cannot break down materials like plastic or pesticides. This means non-biodegradable waste builds up and causes more problems over time.

📝 Teacher's Note: Emphasize that non-biodegradable waste is the biggest problem for our landfills because it never disappears.

🎯 Exam Tip: Always provide clear examples for both, such as "kitchen garbage" for biodegradable and "plastics" for non-biodegradable.

Question 11.
(ii) Quantitative Pollutants and Qualitative Pollutants.
Answer:
Quantitative Pollutants :
1. The excess of \( CO_2 \), Nitrogen oxide etc. pollute the atmosphere.
2. These create unhealthy atmosphere due to the scarcity of oxygen.
Qualitative Pollutants :
1. Use of pesticides, chemical fertilizers pollute the composition of atmosphere.
2. These result in various diseases, e.g. skin cancer asthma etc.
In simple words: Quantitative pollutants are natural things (like \( CO_2 \)) that only become "bad" when there is too much of them. Qualitative pollutants are man-made chemicals (like pesticides) that shouldn't be there at all.

📝 Teacher's Note: Use the analogy of salt in food—a little is fine (natural), but too much is bad (quantitative). Poison is always bad, even in tiny amounts (qualitative).

🎯 Exam Tip: Mention the "excess" of natural gases as the key defining feature of quantitative pollutants.

Question 11.
(iii) Natural Pollution and Anthropogenic Pollution.
Answer:
Natural Pollution :
(a) Cosmic radiation from space and terrestrial radiation pollute the atmosphere.
(b) It disturbs the natural atmosphere and harms human and animal life.
Anthropogenic Pollution :
(a) Man-made pollution is done by radioactive plants, atomic bombs, nuclear fuel etc.
(b) It creates various diseases cancer, heart problems, migraine etc, it also disturbs animal life.
In simple words: Natural pollution happens because of things that exist in nature, like radiation from space. Anthropogenic pollution is just a fancy word for man-made pollution from things like factories and nuclear power.

📝 Teacher's Note: The word "Anthropos" means human, so "Anthropogenic" simply means "born from human actions."

🎯 Exam Tip: Memorize the spelling of "Anthropogenic" as it is a high-scoring keyword for environmental science exams.

II. Long Answer Questions

Question 1. With reference to pollution, explain the following
(a) Air pollution
(b) Water pollution
Answer:
(a) Air pollution is the excessive concentration of foreign matter in the air which adversely affects the well-being of human beings, animals, plants and their environment. Air pollution is caused by addition of chemicals, carbon monoxide, sulphur dioxide, hydrogen sulphide by various factories, industrial plants.
(b) Water pollution is caused by contamination of water by alteration in physical, chemical, biological characteristics of water making it unsuitable for designated use in its natural state.
In simple words: Air pollution involves dangerous gases that harm our health and the world around us. Water pollution happens when chemicals and germs make water unsafe to drink, clean, or swim in.

📝 Teacher's Note: Discuss how both types of pollution are linked; for example, air pollutants can fall into water as acid rain, polluting the water sources.

🎯 Exam Tip: For water pollution, always remember to mention that it makes the water "unsuitable for designated use."

Question 2. Explain clearly what is radioactive pollution. Why is radioactive pollution more harmful than other types of pollutions ?
Answer: Radioactive pollution is caused by cosmic radiation from space, use of radioactive materials which are used in radioactive weapons, nuclear fuel and electric power. Radioactive pollutants remain unperished for a long period, so these are more harmful to spoil natural environment. In t modem age, it has become very difficult to survive in natural state due to production of various radioactive materials for various purposes.
In simple words: This type of pollution is extra dangerous because the radiation stays active for a very long time and cannot be easily cleaned up. It comes from space and high-tech human inventions like nuclear power plants.

📝 Teacher's Note: Explain that "unperished for a long period" means the radiation stays active and dangerous for hundreds or even thousands of years.

🎯 Exam Tip: State clearly that it is "more harmful" specifically because it remains in the environment for such a long time compared to smoke or trash.

Question 3. How is noise a source of pollution ? Why do we need to look at the problem of noise pollution seriously ?
Answer: Noise is a source of pollution because noise pollution is done by extreme noise of industrial sector, transport, loud speakers etc., which adversely affect human health causing severe headache, migraine, mental disbalance, nervous breakdown, heart diseases. Noise is a health hazard. Exposure to prolonged noise has many physical, physiological and psychological effects on human beings in the following ways:
1. repeated exposure to noise reduces the sleeping hours
2. productivity or efficiency of a human being
3. it affects the peace of mind and invades the privacy of a human being.
In simple words: Noise is considered pollution because it is a hazard to our health and well-being. It can stop us from sleeping, reduce our work quality, and take away our mental peace.

📝 Teacher's Note: Discuss the concept of "Peace of Mind" as a basic health requirement that noise pollution disrupts.

🎯 Exam Tip: List the three specific points provided in the book: reduced sleep, lower productivity, and invasion of privacy to secure all marks.

Question 4. How are the pollutants categorised on the basis of their existence in nature. Give two examples of each category?
Answer: Pollutants are categorises in mainly i.e. degradable and non- degradable pollutants, out of them non-degradable pollutants create problem of pollution, e.g. glass, plastics, pesticides etc. On the basis of existence in nature, pollutants are divided into two categories:
• Quantitative pollutants : These substances exist in nature but they act as pollutants when their concentration or quantity increases up to a critical level in the atmosphere, e.g., Carbon- dioxide, Nitrogen oxide, etc.
• Qualitative pollutants : These pollutants do not exist in environment They are introduced into the environment through man’s activities, e.g., pesticides (DDT), chemical fertilizers, herbicides etc.
In simple words: Some pollutants are things already in nature that just become a problem when there is too much of them (Quantitative). Others are purely man-made chemicals that do not exist in nature on their own (Qualitative).

📝 Teacher's Note: Focus on the "critical level" for quantitative pollutants—it means they only become "bad" after crossing a certain amount.

🎯 Exam Tip: Differentiate between substances that "exist in nature" versus those that are "introduced by man" to show a clear distinction.

Question 5. Explain with examples the difference between the primary and secondary pollutants.
Answer: Primary pollutants are directly mixed with atmosphere e.g. smoke, ash, fumes, dust, \( CO_2 \) Sulphur dioxide Methane, Benzene etc. Secondary pollutants are created by automobiles e.g. Nitrogen oxides, hydrocarbons etc, which are more toxic than their original elements.
In simple words: Primary pollutants are "straight from the source" like smoke or dust. Secondary pollutants are born when those original pollutants mix together in the air to form even deadlier chemicals.

📝 Teacher's Note: Think of secondary pollutants as "toxic recipes" made from primary ingredients reacting with each other in the atmosphere.

🎯 Exam Tip: Use "Nitrogen oxides" and "hydrocarbons" as your standard examples for secondary pollutants.

Question 6. What is noise pollution ? How is it caused ?
Answer: Noise pollution is defined as an unwanted sound that is an irritant and a source of stress. Most of the noise originates from modem industrialised urban life. The main sources of noise pollution are :
1. Industrial Sector
2. Transport Sector
3. Household sector
4. Defence Sector
5. Loud Speakers
6. Miscellaneous Sources.
In simple words: Noise is an annoying sound that makes us feel stressed. It mainly comes from our busy city lives, including factory machines, cars, and even household appliances.

📝 Teacher's Note: Ask students to identify noise sources in their own homes, like vacuum cleaners or loud TVs, to make the lesson relatable.

🎯 Exam Tip: List at least four of the six sectors mentioned (e.g., Industrial, Transport, Household, Defence) to provide a comprehensive answer.