Industrial pollution of freshwater can be reduced through the following measures:

1. Treating hot water and effluents before releasing them into rivers and lakes, so that heat and chemicals do not damage aquatic ecosystems.

1. Setting up effluent treatment plants (ETPs) in industries to treat toxic and chemical waste before it is discharged into water bodies.

1. Recycling and reusing water within industrial processes to minimise the volume of wastewater generated and discharged.

1. Strict enforcement of environmental laws — industries must follow pollution control norms set by authorities such as the Central Pollution Control Board.

1. Reducing the use of harmful chemicals in industrial processes and substituting them with eco-friendly alternatives wherever possible.

1. Public awareness and community monitoring of nearby water bodies to ensure industries comply with pollution norms.

For example, industries in river basins like the Ganga and Yamuna have been directed to install ETPs to check water pollution and protect freshwater quality.

Source: Water Resources, Chapter 3

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The textbook mentions that industries pollute freshwater through waste and chemicals, making it hazardous for use. The chapter does not detail specific industrial pollution control steps, so examiners expect general yet relevant scientific measures (ETPs, recycling, law enforcement). Always give at least one example (a river basin/industry) to complete a 5-mark answer. Avoid padding — 5 crisp points + a brief example is ideal for 5 marks.

(C) I-2, II-1, III-4, IV-3

Mahanadi → Hirakud Dam; Narmada → Sardar Sarovar Dam; Chambal → Rana Pratap Sagar Dam; Chenab → Salal Dam.

Source: Water Resources, Chapter 3

The textbook explicitly mentions Hirakud Dam on Mahanadi and Sardar Sarovar Dam on Narmada. Rana Pratap Sagar is a well-known dam on the Chambal River (Rajasthan), and Salal Dam is built on the Chenab River (J&K). Remember these river-dam pairs as they are frequently asked in board exams.

The correct answer is D) Karnataka.

The Tungabhadra Dam is located in the state of Karnataka.

This is a direct factual question. The Tungabhadra Dam is built on the Tungabhadra River in Karnataka. Note that while the source passage does not explicitly name this dam, it is a standard CBSE Class 10 Geography fact. For MCQs, just circle/write the correct option — no explanation needed in the exam.

35.1 Two essential items in a family emergency kit are:

• Torch with spare batteries
• First aid box with essential medicines

35.2 These items are important because during a flood, normal facilities like electricity, medical services, and clean water may not be available. The kit ensures basic survival needs — light, communication, food, and medical care — are met until help arrives.

35.3 Two recommended actions during a flood:

1. Ensure family safety: Move along with family members and cattle to safe areas such as relief camps, evacuation centres, or elevated grounds.
2. Protect belongings and prevent accidents: Keep cash, jewellery, important documents in a safe place and turn off power and gas connections before leaving the house.

Source: Floods — Basic Safety Precautions To Be Taken

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• 35.1 is 1 mark — just name two items directly from the list; no explanation needed.
• 35.2 is 1 mark — give a concise reason (1–2 lines). The key idea is unavailability of normal services during floods.
• 35.3 is 2 marks — describe two actions clearly; each action must be distinct and taken directly from the passage. Name the action + briefly explain it for full credit.
• Always use exact words/phrases from the passage in source-based questions — examiners match them.

Three factors responsible for water pollution are:

1. Domestic Waste: Large urban populations generate huge amounts of sewage and domestic waste that are discharged into rivers and water bodies, making water hazardous for use.

1. Industrial Waste: The ever-increasing number of industries releases chemicals and effluents into freshwater sources, severely polluting them.

1. Agricultural Chemicals: Excessive use of pesticides and fertilisers in agriculture seeps into groundwater and surface water, contaminating them and making water unsafe for human consumption.

Source: Water Scarcity and the Need for Water Conservation and Management, Chapter 3

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The textbook explicitly lists domestic wastes, industrial wastes, chemicals, pesticides and fertilisers as causes of water pollution. Examiners expect students to name each factor clearly and add a brief explanation (one line each). Avoid vague answers — always link the factor to how it pollutes water. Three factors = 1 mark each.

The correctly matched pair is:

A — Gandhi Sagar — Chambal

Gandhi Sagar Dam is built on the Chambal River in Madhya Pradesh. (Hirakud is on Mahanadi; Nagarjuna Sagar is on Krishna; Salal is on Chenab.)

Source: Water Resources, Chapter 3

The textbook mentions Hirakud on the Mahanadi basin, which rules out option B. Nagarjuna Sagar is on the Krishna River (not Kaveri), ruling out C. Salal Project is on the Chenab River (not Beas), ruling out D. Gandhi Sagar on Chambal is the only correct match. Examiners expect you to know the correct river-dam pairing for all major multipurpose projects.

The correct answer is (C) a-iii, b-iv, c-ii, d-i

Sardar Sarovar – Narmada; Salal – Chenab; Gandhi Sagar – Chambal; Hirakud – Mahanadi.

The passage explicitly states Sardar Sarovar is on the Narmada and Hirakud is in the Mahanadi basin. Salal Dam is on the Chenab (Jammu & Kashmir) and Gandhi Sagar is on the Chambal — standard NCERT facts from Chapter 3. Students should memorise dam–river pairs as they appear frequently in MCQs and map-based questions.

(C) Bhopal Lake

Bhopal Lake, one of the largest artificial lakes of its time, was built in the 11th century for water conservation.

The source passage (Hydraulic Structures in Ancient India box) directly states: "In the 11th Century, Bhopal Lake, one of the largest artificial lakes of its time was built." Sambhar and Chilka are natural lakes; Wular is also a natural lake. Bhopal Lake is the only artificial one mentioned, built in the 11th century.

(B) II, IV, I, III

Salal (J&K) → Gandhi Sagar (M.P.) → Pravara (Maharashtra) → Koyna (Maharashtra, further south).

Students must know the approximate latitudinal positions of major dams:

• Salal — Chenab River, Jammu & Kashmir (northernmost)
• Gandhi Sagar — Chambal River, Madhya Pradesh
• Pravara — Pravara River, northern Maharashtra
• Koyna — Koyna River, southern Maharashtra (southernmost among these four)

The textbook map "India: Major Rivers and Dams" (Ch. 3) shows these locations. Eliminate wrong options by anchoring on the northernmost (Salal) and southernmost (Koyna) dams first.

D — Meghalaya

The passage explicitly states: "In Meghalaya, a 200-year-old system of tapping stream and spring water by using bamboo pipes, is prevalent." This is a direct fact-based MCQ — just identify the correct state from the passage.

(35.1) Two methods of traditional water-harvesting used in India:

1. Building diversion channels like kuls and guls in hilly/mountainous regions.
2. Rooftop rainwater harvesting to store drinking water.

(35.2) In Rajasthan, people practised rooftop rainwater harvesting very commonly to store drinking water.

(35.3) Two benefits of rainwater harvesting:

1. Conserves water — harvested rainwater can be stored and used during dry periods, reducing dependence on groundwater.
2. Recharges groundwater — water collected seeps into the ground, raising the water table and ensuring water availability for future use.

Source: Chapter 3 – Water Resources, Contemporary India II

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• (35.1) and (35.2) must be answered directly from the passage — do not go beyond it.
• (35.3) is a 2-mark question requiring two distinct points; examiners expect one clear benefit per point. Benefits like reducing water scarcity, recharging groundwater, or reducing runoff are all accepted.
• Avoid writing long paragraphs; crisp, labelled answers score better in board exams.

(I) Water harvesting system is a viable alternative because it is beneficial both socio-economically and environmentally, overcoming the disadvantages and rising resistance associated with multipurpose projects.

(II) In rooftop rainwater harvesting, rainwater falling on rooftops is collected and stored for use as drinking water. It was commonly practised particularly in Rajasthan.

(III) Two methods adopted by ancient India for water conservation:

• Guls/Kuls — diversion channels built in hill and mountainous regions of the Western Himalayas for agriculture.
• Khadins and Johads — agricultural fields in arid/semi-arid regions were converted into rain-fed storage structures to allow water to stand and moisten the soil.

Source: Water Resources, Rainwater Harvesting section

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• (I) is a direct 1-mark lift from the passage — just pick the exact reason given.
• (II) The passage does not detail the mechanical process; answer only what is stated — collecting rainwater on rooftops for drinking water storage, especially in Rajasthan.
• (III) For 2 marks, name two distinct methods with a brief description each. Guls/Kuls and Khadins/Johads are the clearest examples from the passage. Inundation channels of Bengal is also acceptable as an alternative point.

(35.1) The movement against the Sardar Sarovar Dam project on the Narmada River in Gujarat is known as the Narmada Bachao Andolan.

(35.2) Big dams have been mostly unsuccessful because during excessive rainfall, water has to be released from the reservoirs to prevent overflow. This release itself aggravates the flood situation in downstream areas, as seen in Maharashtra and Gujarat in 2006.

(35.3) Two merits of multi-purpose river projects:

• They help in irrigation, ensuring water supply to agricultural fields throughout the year, increasing crop production.
• They generate hydroelectric power, providing cheap and renewable electricity for industrial and domestic use, contributing to economic development.

Source: Chapter 3 — Water Resources, NCERT Geography Class 10

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• (35.1) is a direct recall question — Narmada Bachao Andolan is the expected answer. The passage mentions Gujarat/Narmada context.
• (35.2) must be answered using the passage itself — the key phrase is "release of water from dams during heavy rains aggravated the flood situation."
• (35.3) asks for merits, which are NOT in the passage (the passage only lists demerits). This tests broader textbook knowledge — irrigation and hydroelectric power generation are the two most standard merits examiners expect. Write one clear point per merit.

(C) Meghalaya

The passage explicitly states: "In Meghalaya, a 200-year-old system of tapping stream and spring water by using bamboo pipes, is prevalent." This is a direct fact — memorise the state name and the key detail (200-year-old system). Source: Bamboo Drip Irrigation System, Chapter 3.

The following steps can be taken to save fresh water from industrial pollution:

1. Treatment of industrial effluents: Industries should treat their waste water in effluent treatment plants before discharging it into rivers or lakes.

1. Strict laws and regulations: The government should enforce strict pollution control laws and penalise industries that dump untreated waste into water bodies.

1. Recycling of water: Industries should reuse and recycle water within their units to minimise the discharge of polluted water.

1. Use of eco-friendly technology: Industries should adopt cleaner production technologies that generate less waste and consume less water.

1. Regular monitoring: Pollution control boards should regularly monitor the quality of water near industrial areas to detect and prevent pollution immediately.

Source: Water Resources, Chapter 3, CBSE Class 10 Geography

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The textbook mentions that industries pollute freshwater through wastes and chemicals, making water hazardous for use. The question is application-based — examiners expect five distinct, clearly labelled points with brief explanations. Each point should be a separate measure (not repeated ideas). Avoid vague answers like "save water"; focus specifically on pollution prevention. No diagrams are needed. One line per point is sufficient for full marks.

The correct option is (D) i-c, ii-d, iii-a, iv-b
Sardar Sarovar – Narmada; Hirakud – Mahanadi; Bhakra Nangal – Sutlej; Nagarjuna Sagar – Krishna.

The textbook explicitly states: Sardar Sarovar Dam is built on the Narmada River; Hirakud project is in the Mahanadi basin; Bhakra–Nangal project is in the Sutlej-Beas river basin. Nagarjuna Sagar is a well-known dam on the Krishna River (standard NCERT fact). Students must memorise dam–river pairings as they are frequently asked in MCQs and match-the-column questions.

(D) To use bamboo drip irrigation system.

The passage clearly states that Meghalaya has a 200-year-old tradition of using bamboo pipes to tap stream and spring water for irrigation — this is the bamboo drip irrigation system. Eliminate other options as they describe general irrigation practices, not specific to Meghalaya. In MCQs, always look for the most specific and textbook-supported option.

Post-independence industrialisation and urbanisation have severely stressed freshwater resources in the following ways:

1. Industries as heavy water users: The ever-increasing number of industries exerts heavy pressure on existing freshwater resources.

1. Demand for hydroelectric power: Industries require large amounts of energy, much of which comes from hydroelectric power, further stressing water resources.

1. Urban population pressure: Multiplying urban centres with large, dense populations and high-consumption lifestyles have greatly increased water and energy requirements.

1. Groundwater depletion: Most urban housing societies use their own groundwater pumping devices, leading to over-exploitation and depletion of fragile groundwater resources in cities.

Thus, industrialisation and urbanisation have together aggravated water scarcity through overuse and depletion.

Source: Water Resources, Chapter 3 — Water Scarcity and the Need for Water Conservation and Management

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• The examiner expects four clear impact points for 3 marks — one point per mark, with a brief concluding line.
• Use textbook language closely: phrases like "exerting pressure on existing freshwater resources" and "fragile water resources are being overexploited" show you have read the chapter.
• Do not write about agriculture or rainfall variation here — the question is specifically about industrialisation and urbanisation.
• Keep each point crisp; no need for lengthy elaboration.

Overuse of Underground Water and Water Crisis:

Overexploitation of groundwater has created a serious crisis across India due to the following reasons:

1. Agriculture demand: Irrigated agriculture is the largest consumer of water. Farmers use own tube-wells and bore-wells to expand irrigation, leading to rapidly falling groundwater levels, threatening food security.

1. Urbanisation: Housing colonies and societies in cities use private groundwater pumping devices excessively, causing depletion of fragile water resources in urban areas.

1. Industrialisation: Ever-increasing industries exert heavy pressure on freshwater and groundwater sources.

Examples in context of Sustainable Development:

• In cities, overuse has led to groundwater depletion, making water unavailable for future generations — violating the principle of sustainable development.
• Atal Bhujal Yojana addresses this by promoting conservation in 8,220 water-stressed Gram Panchayats across 7 states (Gujarat, Rajasthan, Haryana, etc.), shifting communities from consumption to smart water management.
• Sustainable solutions like rooftop rainwater harvesting (e.g., Gendathur, Karnataka; Shillong, Meghalaya) and Pradhan Mantri Krishi Sinchayee Yojana (per drop more crop) reduce dependence on groundwater.

Source: Chapter 3 — Water Scarcity and the Need for Water Conservation and Management

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• The question is split 2+3: 2 marks for explaining the crisis, 3 marks for sustainable development examples/solutions.
• Examiners expect you to mention falling groundwater levels, agriculture/urbanisation/industry as causes, and then link to government schemes or traditional methods as sustainable alternatives.
• Always name specific examples (Atal Bhujal Yojana, PMKSY, Gendathur) — these fetch marks in the 3-mark part.
• Avoid vague statements; be specific about consequences (food security, depletion, health hazards).

Option B — Maharashtra, Madhya Pradesh, Gujarat and Rajasthan

The Sardar Sarovar Dam is built over the Narmada River in Gujarat and covers four states: Maharashtra, Madhya Pradesh, Gujarat and Rajasthan.

Source: Water Resources, Chapter 3 (Sardar Sarovar Dam box)

The textbook explicitly names the four states benefitted by the Sardar Sarovar Project in the highlighted box. Students must remember this specific combination — Punjab and Haryana (Option A) are linked to the Bhakra-Nangal project, not Sardar Sarovar. Eliminate options with Telangana, Andhra Pradesh, Karnataka, or Chhattisgarh, as these are not mentioned in connection with this dam.

The correct answer is C: a-iii, b-iv, c-i, d-ii

Chambal – Gandhi Sagar; Ganga – Tehri; Chenab – Salal; Satluj – Bhakra Nangal.

Students must memorise river-dam pairs. Key ones: Bhakra Nangal is on the Satluj (also called Sutluj), Gandhi Sagar is on the Chambal, Salal is on the Chenab, and Tehri is on the Ganga (Bhagirathi tributary). The textbook specifically mentions the Bhakra-Nangal project in the Sutluj-Beas river basin. The others are standard NCERT Class 10 Geography facts from Chapter 3.

Overuse of Groundwater and Sustainability of Development:

1. Falling groundwater levels: Farmers use tube-wells and borewells extensively for irrigation. Urban housing societies also pump groundwater to meet daily needs, leading to rapid depletion of groundwater levels.

1. Threat to food security: Irrigated agriculture is the largest consumer of water. Over-exploitation of groundwater to expand dry-season agriculture threatens long-term food production and security.

1. Growing population pressure: Large and growing populations demand more water for domestic use and food production, accelerating over-exploitation of this resource.

1. Industrial and urban pressure: Rapid industrialisation and urbanisation have increased pressure on freshwater resources, further depleting groundwater reserves.

1. Ecological crisis: Overexploitation and mismanagement of water resources will impoverish this resource and cause ecological crisis, having a profound impact on lives and livelihoods.

1. Water pollution: Pollution from industrial waste, pesticides, and fertilisers reduces usable water, compounding scarcity.

Thus, sustainable development demands responsible use of groundwater, as its depletion endangers future generations' needs.

Source: Water Resources, Chapter 3 — Water Scarcity and the Need for Water Conservation and Management

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• The examiner expects you to link groundwater overuse to multiple dimensions of sustainability — food security, ecology, population, industry.
• Key phrase from the textbook: "Over exploitation and mismanagement of water resources will impoverish this resource and cause ecological crisis." — quote or paraphrase this directly.
• 5 marks = ~5 distinct, developed points. Avoid vague statements; each point should name the cause AND its consequence.
• End with a concluding line connecting back to the concept of sustainable development (meeting present needs without compromising future generations).

The correct option is (C) a-iv, b-i, c-ii, d-iii

• Hirakud Dam — Mahanadi (iv)
• Gandhi Sagar Dam — Chambal (i)
• Nagarjuna Sagar Dam — Krishna (ii)
• Mettur Dam — Kaveri (iii)

Source: Water Resources, Chapter 3

The textbook mentions Hirakud on the Mahanadi river explicitly. The other matches — Gandhi Sagar on Chambal, Nagarjuna Sagar on Krishna, and Mettur on Kaveri — are standard factual associations from the chapter's map and content. Examiners expect you to have memorised major dam–river pairs. Option (C) is the only one with all four correctly matched.

18.1 Floods cause extensive soil erosion and lead to sedimentation. This deprives flood plains of silt — a natural fertilizer — thus contributing to land degradation.

18.2 Irrigation has shifted farmers towards water-intensive and commercial crops. This has led to ecological consequences like salinisation of the soil, degrading agricultural land.

18.3 Two objectives of PM Krishi Sinchayee Yojana:

• Har Khet Ko Pani: To enhance physical access of water on the farm and expand cultivable area under assured irrigation.
• Per Drop More Crop: To improve on-farm water use efficiency, reduce wastage, and promote water-saving irrigation technologies and sustainable water conservation practices.

Source: Water Resources, Pradhan Mantri Krishi Sinchayee Yojana (extract)

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• 18.1 focuses on the two-step process: soil erosion + loss of silt = land degradation. Both points needed for full credit.
• 18.2 The key terms examiners look for are "water-intensive/commercial crops" and "salinisation."
• 18.3 Use the scheme's own slogans (har khet ko pani, per drop more crop) — examiners reward these as they are from the prescribed text. Each objective should be explained briefly, not just named.

18.1 Use boiled and filtered drinking water after floods.

18.2 Two measures to protect food during floods:

1. Eat freshly cooked and dry food.
2. Always keep your food covered.

18.3 Two actions to be taken before leaving the house during a flood warning:

1. Keep cash, jewellery, valuables, and important documents in a safe place.
2. Turn off power and gas connections before leaving the house.

Source: Floods – Basic Safety Precautions / During Floods

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• 18.1 is 1 mark — one clean, direct line from the passage suffices.
• 18.2 is also 1 mark for two points — keep both points brief; examiners award the mark if both are present.
• 18.3 is 2 marks — one mark per action. Draw only from the "Basic safety precautions" section. Avoid mixing with "during floods" points. Writing clearly numbered actions ensures you don't lose marks.
• Always use the exact language of the passage in source-based questions — it shows you've read carefully and prevents errors.

18.1 Sardar Sarovar Project is important for Gujarat because it provides irrigation to 18.45 lakh hectares covering 3112 villages in 15 districts, and about 75% of its command area is drought prone, so the project will make it drought proof.

18.2 The project covers four states — Maharashtra, Madhya Pradesh, Gujarat and Rajasthan — because the Narmada river flows through all these states and its water resources need to be shared equitably to meet the water requirements of their drought prone and desert areas.

18.3 The project promotes sustainability by:

• Providing assured water supply to drought prone areas, making them drought proof in the long run.
• Irrigating tribal hilly tracts of Maharashtra and desert districts of Rajasthan, ensuring long-term agricultural stability.
• Covering a large multi-state region, promoting balanced and sustainable water resource management across 18.45 lakh hectares of land.

Source: Sardar Sarovar Project (Water Resources, Chapter 3)

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• 18.1: Pick the specific Gujarat-related statistics from the passage (18.45 lakh ha, 3112 villages, drought prone area) — examiners want data, not vague statements.
• 18.2: The passage says it covers four states; reason out the inter-state water sharing angle from the passage context (drought prone/desert areas across states).
• 18.3 (2 marks): Give two distinct points scaled to 1 mark each — drought proofing and long-term agricultural/water sustainability. Avoid going beyond the passage; examiners expect source-based answers.