Updated NCERT Solutions for Class 11 Geography Chapter 15: India – State of Environment | Important Questions 2026-27
Welcome, future geographers! This chapter explores the critical state of India's environment. We'll break down complex topics like pollution and degradation into simple, easy-to-understand points. This guide provides updated NCERT solutions and important questions to help you ace your exams and understand our country's environmental challenges better.
Chapter NameIndia – State of Environment
SubjectGeography (Book: India Physical Environment)
Class11
BoardCBSE
Important TopicsPollution (Water, Air, Noise, Land), Urban Waste, Land Degradation, Case Studies (Ganga, Delhi Smog)
Difficulty LevelModerate
Exam Weightage3-5 marks
Learning Objectives
After completing this chapter, students will be able to:
- Define environmental pollution and its different types.
- Identify the primary sources of air, water, land, and noise pollution in India.
- Explain the severe consequences of pollution on human health and the ecosystem.
- Analyse the problem of urban waste disposal and its impact.
- Understand the causes and effects of land degradation in various parts of India.
- Discuss government initiatives and solutions to tackle these environmental issues.
Key Concepts & Definitions
Let's get familiar with some important terms from this chapter.
- Pollution: The introduction of harmful materials or contaminants into the environment, causing adverse change.
- Pollutants: Substances that cause pollution. They can be solid, liquid, or gas.
- Water Pollution: The contamination of water bodies (like rivers, lakes, oceans, and groundwater) by harmful substances. Main sources in India are urban sewage and industrial effluents.
- Air Pollution: The presence of harmful substances in the air, like Sulphur Oxides (SOx), Nitrogen Oxides (NOx), and Carbon Monoxide (CO), mainly from industries and vehicles.
- Smog: A type of intense air pollution, which is a mixture of smoke and fog. Often seen in big cities like Delhi during winter.
- Acid Rain: Rain that is unusually acidic due to pollutants like Sulphur Dioxide and Nitrogen Oxide reacting with water in the atmosphere.
- Noise Pollution: Unwanted or excessive sound that can have harmful effects on human health and environmental quality. Its intensity is measured in decibels (dB).
- Land Degradation: The deterioration or loss of the productive capacity of the soil for present and future use. It can be caused by natural hazards or human activities.
- Eutrophication: The process where a water body becomes overly enriched with minerals and nutrients, which induces excessive growth of algae. This leads to oxygen depletion in the water.
FULL NCERT SOLUTIONS (Exercise Questions)
Here are the detailed, board-exam-style answers to all the questions from your NCERT textbook exercise.
1. Choose the right answers of the following from the given options.
(i) Which one of the following river is highly polluted?
(a) Brahmaputra
(b) Satluj
(c) Yamuna
(d) Godavari
Answer: (c) Yamuna. The Yamuna is one of India's most polluted rivers, especially as it passes through Delhi, Agra, and Mathura. It receives a massive amount of untreated sewage, industrial waste, and solid waste, leading to extremely low levels of dissolved oxygen and high biological oxygen demand (BOD).
(ii) Which one of the following diseases is caused by water pollution?
(a) Conjunctivitis
(b) Diarrhoea
(c) Respiratory infections
(d) Bronchitis
Answer: (b) Diarrhoea. Water-borne diseases are caused by consuming contaminated water. Diarrhoea, cholera, typhoid, and hepatitis are common examples. The other options are related to air pollution (respiratory infections, bronchitis) or other infections (conjunctivitis).
(iii) Which one of the following is the cause of acid rain?
(a) Water pollution
(b) Land pollution
(c) Noise pollution
(d) Air pollution
Answer: (d) Air pollution. Acid rain is a direct consequence of air pollution. When pollutants like Sulphur Dioxide (SO₂) and Nitrogen Oxides (NOx) are released into the atmosphere from burning fossil fuels, they react with water, oxygen, and other chemicals to form sulfuric and nitric acids. These acids then mix with rain, making it acidic.
(iv) Push and pull factors are responsible for–
(a) Migration
(b) Land degradation
(c) Slums
(d) Air pollution
Answer: (a) Migration. Push factors (like poverty, unemployment, lack of facilities in villages) "push" people away from their homes. Pull factors (like job opportunities, better education, and healthcare in cities) "pull" them towards urban areas. This entire process is known as migration.
2. Answer the following questions in about 30 words.
(i) What is pollution?
Answer: Pollution is the introduction of harmful substances or contaminants into the natural environment that causes adverse or undesirable changes. These contaminants, known as pollutants, can damage the quality of air, water, and land, negatively impacting human health and the ecosystem. For example, smoke from factories pollutes the air.
(ii) Name the three types of pollution.
Answer: The three main types of pollution are:
1. Air Pollution: Contamination of the air by harmful gases and particulate matter.
2. Water Pollution: Contamination of water bodies like rivers and lakes.
3. Land Pollution: Degradation of the Earth's land surfaces through misuse or disposal of waste.
Another significant type is Noise Pollution.
1. Air Pollution: Contamination of the air by harmful gases and particulate matter.
2. Water Pollution: Contamination of water bodies like rivers and lakes.
3. Land Pollution: Degradation of the Earth's land surfaces through misuse or disposal of waste.
Another significant type is Noise Pollution.
(iii) What are the major sources of water pollution in India?
Answer: The major sources of water pollution in India are:
- Domestic/Urban Sewage: Untreated wastewater from households in cities and towns is the largest source.
- Industrial Effluents: Toxic chemicals and waste discharged from industries like tanneries, chemical plants, and refineries.
- Agricultural Runoff: Fertilizers and pesticides from farms get washed into nearby water bodies.
(iv) Mention major problems associated with urban waste disposal in India.
Answer: Major problems associated with urban waste disposal in India include:
- Overfilled Landfills: Most cities are running out of space for landfills, which are overflowing and unhygienic.
- Air and Water Pollution: Burning waste releases toxic gases, and leachate from landfills contaminates groundwater.
- Health Hazards: Improper waste disposal leads to the spread of diseases by flies, rodents, and mosquitoes.
3. Answer the following questions in about 150 words.
(i) What is the state of India's environment?
Answer: The state of India's environment is a matter of serious concern, facing challenges on multiple fronts due to rapid industrialization, urbanization, and a large population.
While the government has launched initiatives like the 'Namami Gange' programme and the 'National Clean Air Programme', the scale of the problem requires more stringent implementation and public participation to achieve a sustainable environment.
- Threat of Pollution: India is grappling with severe air, water, land, and noise pollution. Major rivers like the Ganga and Yamuna are heavily polluted with industrial and domestic waste. Air quality in metropolitan cities, especially Delhi, often reaches hazardous levels due to vehicular emissions, industrial smoke, and crop burning.
- Resource Depletion: There is immense pressure on natural resources. Forests are being cleared for agriculture and infrastructure, leading to deforestation and loss of biodiversity. Water tables are declining rapidly due to over-extraction for irrigation and urban needs.
- Land Degradation: A significant percentage of India's land is degraded due to soil erosion, waterlogging, and salinization caused by unscientific agricultural practices and deforestation.
- Waste Management Crisis: The management of solid waste, particularly in urban areas, is a colossal challenge. Overburdened landfills and lack of proper segregation and recycling mechanisms contribute to land and water pollution.
While the government has launched initiatives like the 'Namami Gange' programme and the 'National Clean Air Programme', the scale of the problem requires more stringent implementation and public participation to achieve a sustainable environment.
(ii) What are the causes of water pollution in India? Explain.
Answer: Water pollution in India is a widespread problem with multiple causes, primarily linked to human activities. The main causes are:
1. Urbanisation and Sewage: A major cause is the discharge of untreated or partially treated sewage from cities and towns directly into rivers and lakes. With rapid urban growth, the existing sewage treatment capacity is inadequate. This domestic waste contains organic matter, detergents, and pathogens, which deplete the oxygen in the water, harming aquatic life.
2. Industrial Effluents: Industries are a significant source of toxic pollutants. Tanneries, chemical plants, textile mills, refineries, and slaughterhouses often discharge untreated effluents containing heavy metals (like lead, mercury), acids, alkalis, and other harmful chemicals. These pollutants are non-biodegradable and persist in the environment, contaminating both surface and groundwater.
3. Agricultural Runoff: The modern agricultural system relies heavily on chemical fertilizers, pesticides, and insecticides. During rainfall or irrigation, these chemicals wash off the fields and enter rivers, lakes, and groundwater. This process, known as agricultural runoff, leads to eutrophication, where excess nutrients cause algal blooms that suffocate aquatic ecosystems.
4. Religious and Social Practices: Activities like idol immersion during festivals and the disposal of dead bodies and other materials in rivers like the Ganga contribute to pollution. While culturally significant, these practices add to the pollution load of the rivers.
5. Thermal Pollution: Water used as a coolant in thermal power plants is discharged back into rivers at a higher temperature. This thermal pollution reduces the dissolved oxygen content of the water, affecting fish and other aquatic organisms.
1. Urbanisation and Sewage: A major cause is the discharge of untreated or partially treated sewage from cities and towns directly into rivers and lakes. With rapid urban growth, the existing sewage treatment capacity is inadequate. This domestic waste contains organic matter, detergents, and pathogens, which deplete the oxygen in the water, harming aquatic life.
2. Industrial Effluents: Industries are a significant source of toxic pollutants. Tanneries, chemical plants, textile mills, refineries, and slaughterhouses often discharge untreated effluents containing heavy metals (like lead, mercury), acids, alkalis, and other harmful chemicals. These pollutants are non-biodegradable and persist in the environment, contaminating both surface and groundwater.
3. Agricultural Runoff: The modern agricultural system relies heavily on chemical fertilizers, pesticides, and insecticides. During rainfall or irrigation, these chemicals wash off the fields and enter rivers, lakes, and groundwater. This process, known as agricultural runoff, leads to eutrophication, where excess nutrients cause algal blooms that suffocate aquatic ecosystems.
4. Religious and Social Practices: Activities like idol immersion during festivals and the disposal of dead bodies and other materials in rivers like the Ganga contribute to pollution. While culturally significant, these practices add to the pollution load of the rivers.
5. Thermal Pollution: Water used as a coolant in thermal power plants is discharged back into rivers at a higher temperature. This thermal pollution reduces the dissolved oxygen content of the water, affecting fish and other aquatic organisms.
Extra Important Questions (Board Style) for 2026-27
Multiple Choice Questions (MCQs)
1. Which city in India is often cited for severe smog-related air pollution issues, especially during winter?
(a) Chennai
(b) Mumbai
(c) Delhi
(d) Bengaluru
Answer: (c) Delhi. The combination of vehicular pollution, industrial emissions, and stubble burning in neighbouring states leads to thick smog in Delhi.
2. The process where a water body gets overly enriched with nutrients, leading to excessive algae growth, is called:
(a) Salinisation
(b) Eutrophication
(c) Acidification
(d) Degradation
Answer: (b) Eutrophication.
3. Which of the following is a major cause of land degradation in states like Punjab and Haryana?
(a) Deforestation
(b) Over-irrigation leading to waterlogging and salinity
(c) Jhum cultivation
(d) Mining activities
Answer: (b) Over-irrigation leading to waterlogging and salinity. The Green Revolution led to intensive irrigation, which has caused these issues.
4. The 'Namami Gange' Programme was launched by the Government of India primarily to:
(a) Promote tourism along the Ganga
(b) Build more dams on the Ganga
(c) Clean and rejuvenate the River Ganga
(d) Create new shipping routes
Answer: (c) Clean and rejuvenate the River Ganga.
5. Noise is measured in which unit?
(a) Joules
(b) Pascals
(c) Hertz
(d) Decibels (dB)
Answer: (d) Decibels (dB).
Short Answer Questions
6. What are 'push' and 'pull' factors of migration? Give one example of each.
Answer: 'Push' factors are negative conditions that compel people to leave their place of origin (e.g., poverty, unemployment). 'Pull' factors are positive attractions of a destination that draw migrants to it (e.g., better job opportunities, education).
7. How does urbanisation contribute to water pollution?
Answer: Urbanisation leads to a massive concentration of population, generating huge amounts of domestic sewage. Often, cities lack adequate sewage treatment plants, so this untreated wastewater is discharged directly into nearby rivers, severely polluting them.
8. What is land degradation? Name two human activities that cause it.
Answer: Land degradation is the decline in the productive capacity and quality of land. Two human activities that cause it are:
- Deforestation: Clearing forests for agriculture or urban development.
- Overgrazing: Allowing too much livestock to graze on a piece of land, which removes vegetation and leads to soil erosion.
9. Differentiate between biodegradable and non-biodegradable pollutants.
Answer: Biodegradable pollutants (e.g., sewage, paper) can be broken down into simpler, harmless substances by natural processes. Non-biodegradable pollutants (e.g., plastics, heavy metals) cannot be broken down by natural processes and persist in the environment for a long time.
10. Why is noise pollution a problem in urban areas?
Answer: Noise pollution is a major problem in urban areas due to high traffic density, industrial activities, construction work, and use of loudspeakers. It can cause health issues like stress, hypertension, hearing loss, and sleep disturbances.
Long Answer & Case-Based Questions
11. "Air pollution in India is not just an urban problem but also a rural one." Justify this statement with suitable examples.
Answer: While air pollution is often associated with cities, rural areas in India also face significant challenges.
- Urban Sources: Cities are hotspots due to high vehicle density, industrial emissions, and construction dust. The burning of fossil fuels in power plants and industries releases pollutants like SOx, NOx, and particulate matter.
- Rural Sources: In rural areas, a primary source of indoor air pollution is the use of traditional biofuels like firewood, cow dung cakes, and crop residue for cooking and heating. This releases harmful smoke and particulate matter inside homes, causing severe respiratory illnesses, especially among women and children.
- Agricultural Practices: The practice of 'stubble burning' or 'parali' burning, especially in states like Punjab and Haryana, is a major seasonal source of air pollution that affects not only the rural areas but also contributes to the severe smog in distant cities like Delhi.
- Brick Kilns and Small Industries: Many rural and semi-urban areas have brick kilns and small-scale industries that often use inefficient technology and low-quality fuel, releasing large amounts of black smoke and pollutants into the atmosphere.
12. Explain the main causes of land degradation in India. Suggest some measures for its control.
Answer: Land degradation is a serious environmental issue in India, stemming from both natural and man-made causes.
Main Causes:
1. Soil Erosion: This is the most significant cause. Deforestation, overgrazing, and unscientific farming practices (like shifting cultivation) leave the topsoil exposed to wind and water, which carry it away.
2. Waterlogging and Salinity: In canal-irrigated areas like Punjab and Haryana, excessive irrigation raises the water table. This brings salts to the surface through capillary action, making the land saline and unproductive.
3. Deforestation: The clearing of forests for agriculture, industry, and urban expansion removes the protective vegetation cover, accelerating soil erosion and disturbing the ecological balance.
4. Improper Land Use: Shifting cultivation (Jhum) in North-Eastern states involves clearing and burning forest patches, which degrades the land after a few cycles.
5. Industrial and Urban Waste: Dumping of untreated industrial waste and urban solid waste on land contaminates it with toxic chemicals and makes it unfit for use.
Control Measures:
1. Afforestation and Reforestation: Planting more trees helps bind the soil and reduces erosion.
2. Sustainable Agricultural Practices: Promoting techniques like crop rotation, contour ploughing, and terrace farming can conserve soil and water.
3. Proper Water Management: Using efficient irrigation methods like drip and sprinkler irrigation can prevent waterlogging and salinity.
4. Reclamation of Waste Land: Degraded lands can be reclaimed through specific programmes for soil amendment and revegetation.
5. Regulated Grazing: Managing grazing by livestock can prevent the destruction of grasslands.
Main Causes:
1. Soil Erosion: This is the most significant cause. Deforestation, overgrazing, and unscientific farming practices (like shifting cultivation) leave the topsoil exposed to wind and water, which carry it away.
2. Waterlogging and Salinity: In canal-irrigated areas like Punjab and Haryana, excessive irrigation raises the water table. This brings salts to the surface through capillary action, making the land saline and unproductive.
3. Deforestation: The clearing of forests for agriculture, industry, and urban expansion removes the protective vegetation cover, accelerating soil erosion and disturbing the ecological balance.
4. Improper Land Use: Shifting cultivation (Jhum) in North-Eastern states involves clearing and burning forest patches, which degrades the land after a few cycles.
5. Industrial and Urban Waste: Dumping of untreated industrial waste and urban solid waste on land contaminates it with toxic chemicals and makes it unfit for use.
Control Measures:
1. Afforestation and Reforestation: Planting more trees helps bind the soil and reduces erosion.
2. Sustainable Agricultural Practices: Promoting techniques like crop rotation, contour ploughing, and terrace farming can conserve soil and water.
3. Proper Water Management: Using efficient irrigation methods like drip and sprinkler irrigation can prevent waterlogging and salinity.
4. Reclamation of Waste Land: Degraded lands can be reclaimed through specific programmes for soil amendment and revegetation.
5. Regulated Grazing: Managing grazing by livestock can prevent the destruction of grasslands.
Case-Based/Source-Based Questions
Instructions: Read the passage below and answer the questions that follow.
A recent report highlighted that a massive 'garbage mountain' at a landfill site on the outskirts of a major Indian metropolis is now taller than a multi-storey building. This landfill receives thousands of tonnes of mixed waste every day. Leachate, a toxic liquid, seeps from the bottom of the landfill, contaminating the groundwater in the nearby residential colonies. Frequent fires at the landfill release poisonous smoke, causing respiratory problems for the residents.
13. (a) Identify the two types of pollution being caused by the landfill described in the passage.
Answer: The two types of pollution are Land Pollution (the garbage mountain itself) and Water Pollution (contamination of groundwater by leachate). Air pollution is also being caused by the fires.
(b) What is 'leachate' and why is it dangerous?
Answer: Leachate is the toxic liquid that forms when rainwater filters through the waste in a landfill. It is dangerous because it contains dissolved chemicals, heavy metals, and other harmful substances from the waste, which can contaminate groundwater and soil, making water unsafe for drinking.
(c) Suggest two sustainable solutions to the problem of urban waste instead of dumping it in landfills.
Answer: Two sustainable solutions are:
1. Waste Segregation at Source: Separating waste into dry (plastic, paper), wet (kitchen waste), and hazardous categories at the household level.
2. 3R Principle (Reduce, Reuse, Recycle): Wet waste can be composted, and dry waste can be recycled, significantly reducing the amount of garbage that needs to be sent to landfills.
1. Waste Segregation at Source: Separating waste into dry (plastic, paper), wet (kitchen waste), and hazardous categories at the household level.
2. 3R Principle (Reduce, Reuse, Recycle): Wet waste can be composted, and dry waste can be recycled, significantly reducing the amount of garbage that needs to be sent to landfills.
Instructions: Read the passage below and answer the questions that follow.
During October-November, the Air Quality Index (AQI) in Delhi often crosses the 'Severe' category. Schools are shut down, and a public health emergency is declared. A major contributing factor is the burning of paddy stubble (parali) by farmers in the neighbouring states of Punjab and Haryana after the harvest.
14. (a) What is stubble burning and why do farmers practice it?
Answer: Stubble burning is the act of setting fire to the straw stubble left after harvesting grains like paddy (rice). Farmers practice it as a quick and cheap method to clear their fields to sow the next crop, which is usually wheat.
(b) How does this activity in Punjab and Haryana lead to air pollution in Delhi?
Answer: The smoke and particulate matter (PM2.5) from the large-scale burning of stubble are carried by north-westerly winds towards the National Capital Region. During winter, lower temperatures and slower wind speeds trap these pollutants close to the ground, leading to the formation of a thick layer of smog and a drastic spike in air pollution in Delhi.
15. "Development and environment are two sides of the same coin." Explain the statement in the context of India's environmental problems.
Answer: This statement implies that development cannot be achieved at the cost of the environment, and environmental protection cannot happen by halting development. They must go hand-in-hand.
In India, the pursuit of rapid economic development has often led to significant environmental degradation.
In India, the pursuit of rapid economic development has often led to significant environmental degradation.
- Industrialisation: While creating jobs and growth, industries have polluted our rivers and air.
- Urbanisation: While creating modern cities, it has led to slums, waste management crises, and pressure on resources.
- Agriculture: The Green Revolution increased food production but also caused land degradation and water pollution through excessive use of chemicals and water.
- Adopting cleaner technologies in industries.
- Investing in renewable energy sources like solar and wind.
- Promoting sustainable urban planning and public transport.
- Encouraging organic and sustainable farming.
Common Mistakes Students Make
- Confusing Causes and Effects: Students often mix up the causes of pollution (e.g., industrial waste) with its effects (e.g., death of fish). Make a clear chart for each pollution type with separate columns for sources and consequences.
- Giving Vague Answers: Instead of saying "pollution is bad," provide specific examples. For instance, "Air pollution in Delhi from vehicles and stubble burning leads to respiratory diseases like asthma."
- Ignoring Indian Context: This chapter is "India – State of Environment." Always use examples from India (Ganga, Yamuna, Delhi, Jharia coalfields) as mentioned in the NCERT book.
- Mixing up Land Degradation and Land Pollution: Land pollution is contamination by waste. Land degradation is the loss of soil productivity due to erosion, salinity, etc. They are related but distinct.
Exam Preparation Tips
- Mind Maps: Create mind maps for Air, Water, and Land pollution. Branch out with causes, effects, and solutions for each.
- Case Studies are Key: Pay special attention to the case studies mentioned, like the pollution of the Ganga and Yamuna, and urban waste in cities. Questions are often framed around these.
- Focus on Definitions: Be very clear with the definitions of key terms like Eutrophication, Smog, Acid Rain, and Land Degradation.
- Practice Writing: The 150-word answers require a structured approach. Practice writing them with an introduction, a body with 3-4 points, and a conclusion.
- Last-Minute Revision: Before the exam, quickly go through your mind maps, key definitions, and the NCERT solutions provided here.
Frequently Asked Questions (FAQs)
Q1: What is the main cause of land degradation in India?
The single largest cause of land degradation in India is soil erosion caused by water and wind, which is often accelerated by human activities like deforestation and overgrazing.
Q2: Why is the River Yamuna more polluted than the River Ganga?
While both are polluted, the Yamuna is considered more polluted because it has less fresh water flow for most of the year. It receives enormous quantities of untreated sewage and industrial waste, especially in the stretch passing through Delhi, which turns it into a virtual sewer.
Q3: What is the difference between smog and fog?
Fog is a natural phenomenon consisting of tiny water droplets suspended in the air. Smog (a combination of 'smoke' and 'fog') is air pollution that reduces visibility; it's a mixture of smoke, pollutants like nitrogen oxides, and fog.
Q4: What steps is the government taking to control air pollution?
The government has launched the National Clean Air Programme (NCAP) to reduce particulate matter concentration. Other steps include promoting cleaner BS-VI fuel for vehicles, expanding the metro network in cities, and providing subsidies to farmers for alternatives to stubble burning.
Q5: How can I, as a student, help reduce environmental pollution?
You can contribute by practicing the 3Rs (Reduce, Reuse, Recycle), saving electricity and water, planting trees, using public transport or cycling for short distances, and spreading awareness among your family and friends.
Conclusion: Understanding the state of India's environment is crucial not just for your exams but also for being a responsible citizen. This chapter highlights the urgent need for sustainable practices. By thoroughly understanding the causes and consequences of environmental degradation, we can all contribute to finding effective solutions. Revise these notes regularly, practice the important questions, and you'll be well-prepared for your exams and for making a positive impact on our planet.