Nature’s Treasures – Case-based Questions with Answers
Nature's Treasures — 20 Case-Based Questions & Answers
Scenario-based questions with clear answers to build analytical skills and exam readiness. Prepared strictly as per NCERT for CBSE Class 6.
Case 1
Riya notices that her village pond has become dirty due to nearby sewage disposal. Fish are dying and people complain about bad smell.
Q1: What type of pollution is this? A: Water pollution — contamination of freshwater by sewage and waste.
Q2: Suggest two immediate actions to improve the situation. A: Stop sewage discharge into the pond and set up a basic filtration or constructed wetland; organise a clean-up drive and raise awareness.
Case 2
A school records a steady fall in water levels of a nearby well over years. Farmers nearby dig deeper wells to get water.
Q1: What is the likely reason for falling water table? A: Excessive groundwater extraction and insufficient recharge due to overuse and less rainwater harvesting.
Q2: What measures can the community take? A: Adopt rainwater harvesting, recharge wells, reduce wastage and use drip irrigation to conserve water.
Case 3
An industrial area discharges colored wastewater into a small stream that flows into a river used for irrigation.
Q1: How can such discharge affect farmers? A: Contaminated water can harm crops, reduce soil fertility and enter the food chain affecting health.
Q2: Mention a regulatory and a practical solution. A: Enforce laws to treat industrial effluents; install effluent treatment plants and monitor quality before discharge.
Case 4
During winter, a town faces thick smog due to vehicle smoke and burning of crop residues nearby.
Q1: What causes smog and why is it harmful? A: Smog is caused by smoke, dust and chemical pollutants combined with fog; it causes respiratory problems and reduces visibility.
Q2: Suggest two ways to reduce smog. A: Promote public transport and ban open burning of crop residues; encourage cleaner fuels and planting trees.
Case 5
A factory emits black soot that settles on leaves of nearby plants and on roof tops.
Q1: What immediate effect does soot have on plants? A: Soot blocks sunlight on leaf surfaces, reducing photosynthesis and plant health.
Q2: How can the factory reduce soot emissions? A: Use filters or electrostatic precipitators, switch to cleaner fuels and follow emission norms.
Case 6
Children in a locality complain of cough and eye irritation; tests show high levels of particulate matter (PM).
Q1: What does high PM indicate? A: Presence of fine dust and particles harmful to lungs and eyes.
Q2: Name one community-level preventive action. A: Create green buffers with trees and limit vehicle movement in high-exposure zones.
Case 7
A hillside farm reports loss of productive topsoil after heavy rains; crops yield less.
Q1: What is this process called? A: Soil erosion — removal of top fertile soil by water.
Q2: Recommend two soil conservation methods. A: Terrace farming and planting cover crops/trees to reduce runoff and bind soil.
Case 8
A patch of agricultural land shows poor plant growth despite regular watering; soil tests show low organic matter.
Q1: What can improve soil fertility? A: Adding compost or organic manure, crop rotation and green manuring to restore nutrients.
Q2: Why is composting beneficial? A: Compost adds humus, improves structure, water retention and supplies nutrients to plants.
Case 9
A building project removes vegetation from a large area leaving exposed soil prone to wind erosion.
Q1: What environmental problem may follow? A: Increased dust, loss of topsoil and reduced local air quality.
Q2: What preventive action should builders take? A: Preserve vegetation where possible, use silt fences, replant native species and control dust with water sprays.
Case 10
A town depends on a nearby mine for jobs but the mine causes water contamination and landscape changes.
Q1: Identify the conflict shown. A: Economic benefit vs environmental protection — jobs versus pollution and habitat loss.
Q2: Suggest balanced solutions. A: Implement cleaner mining, proper waste treatment, rehabilitation of mined sites and community development funds.
Case 11
Students find many aluminium cans and plastic bottles littering their playground and discuss recycling.
Q1: How does recycling help in this case? A: Recycling reduces waste, conserves resources, and prevents littering and pollution.
Q2: What can the school implement? A: Set up segregation bins, run awareness drives and connect with local recyclers for collection.
Case 12
A community faces shortage of building materials; quarrying is proposed nearby but residents fear loss of farmland.
Q1: What are the trade-offs? A: Access to materials and jobs versus loss of farmland, habitats and possible pollution.
Q2: How can planners reduce harm? A: Choose less sensitive sites, limit quarry size, ensure rehabilitation and compensate affected farmers.
Case 13
An area of native forest is cleared to plant a single crop across large fields.
Q1: What impact does this monoculture practice have on biodiversity? A: It reduces biodiversity, making ecosystems more fragile and reducing habitat variety.
Q2: What alternative practice helps both yield and biodiversity? A: Agroforestry or mixed cropping combines trees with crops, improving diversity and soil health.
Case 14
Local people harvest wild medicinal plants aggressively for sale, leading to fewer plants each year.
Q1: What is the long-term risk? A: Overharvesting may lead to extinction of species and loss of traditional medicines.
Q2: Recommend a sustainable approach. A: Cultivate medicinal plants in home gardens and regulate wild collection with permits and quotas.
Case 15
Students notice fewer butterflies in their neighbourhood after many hedges were removed for road widening.
Q1: Why did butterflies decline? A: Loss of flowering plants and habitat reduced nectar and breeding sites.
Q2: What simple action can restore them? A: Plant native flowering shrubs and create small 'pollinator patches' near roadsides and schools.
Case 16
A village uses kerosene lamps for lighting while a sunlight-rich hill nearby could support solar lighting projects.
Q1: Why is solar power preferable? A: Solar is renewable, reduces pollution and long-term costs, and uses abundant local resource.
Q2: What steps to introduce solar? A: Conduct feasibility, arrange subsidies/loans, install community solar panels and train locals for maintenance.
Case 17
A city plans to ban single-use plastic bags to cut plastic pollution but small shops worry about customer inconvenience.
Q1: How does banning plastic help the environment? A: Reduces litter, protects wildlife and lowers microplastic pollution in soil and water.
Q2: How can transition be smooth for shops? A: Offer affordable cloth or paper bag alternatives, run awareness and provide a transition period with incentives.
Case 18
Residents report frequent flooding in low-lying areas after drainage channels were blocked by garbage.
Q1: Why did blockage increase flood risk? A: Blocked drains prevent water flow, causing water to accumulate and flood areas during heavy rains.
Q2: What community actions prevent this? A: Regular cleaning of drains, public awareness to avoid dumping waste, and installing trash traps.
Case 19
A school's cafeteria throws leftover food and plastic plates into the general bin every day.
Q1: What environmental problems arise? A: Increased landfill waste, methane from rotting food, and plastic pollution.
Q2: Suggest a practical waste-management plan for the school. A: Separate organic waste for composting, send recyclables to recyclers, and switch to reusable plates/cutlery.
Case 20
Pupils observe that their playground has fewer trees than before and summers feel hotter.
Q1: How does tree loss affect local climate? A: Fewer trees reduce shade and evapotranspiration, increasing local temperatures and reducing comfort.
Q2: Propose a school-led plan to improve green cover. A: Organise tree-planting drives with native species, make a maintenance roster, and engage community volunteers.