Floods to Green Hydrogen: Environment, Disasters and Energy GK for Sainik School

Environment questions — natural disasters, water pollution, energy sources and life in the mountains — appear in the GK and EVS part of the AISSEE (Sainik School) Class 6 syllabus and in the RMS CET. This guide explains each topic simply, with examples from recent news and a revision table at the end.

1. Natural Calamities: Floods, Earthquakes & Other Disasters

Overview

• Natural calamities are sudden, severe geological or climatic events caused by natural Earth processes that cause widespread damage to life, property and the environment.

• The National Disaster Management Authority (NDMA), under the Ministry of Home Affairs, is India's apex body for disaster preparedness. It issues Standard Operating Procedures (SOPs) for disaster management and Disaster Victim Identification (DVI).

Floods

• Causes: Heavy monsoon rain, rivers overflowing their banks, poor urban drainage, dam breaches and Glacial Lake Outburst Floods (GLOFs) from growing high-altitude glacial lakes (such as the Mago Chu basin in Tawang and South Lhonak Lake).

• Inland Tsunamis & Mass Collapses: Sudden collapses of glaciers and rock (such as the Langtang Lirung event) can send huge surges into rivers, creating destructive flood waves.

• Impacts & Early Warning: Floods cause soil erosion, crop loss, displacement and waterborne diseases. Tools like SIVAS (Swell-Surge Inundation Vulnerability Advisory System) give real-time coastal flood warnings.

Earthquakes

• Cause: The sudden release of energy along fault lines in the Earth's crust due to tectonic plate movement. The underground point where the slip starts is the Focus (Hypocentre); the point directly above it on the surface is the Epicentre.

• Crustal Earthquakes: Occur in the crust (0–35 km deep) when brittle rocks fracture; they cause the most surface damage.

• Deep-Focus Earthquakes: Occur deep in the mantle (70–700 km) along subduction zones such as the Pacific Ring of Fire.

• Doublet Earthquakes: Two large earthquakes of similar size close together in time and place, caused by stress transfer along faults (for example, in Venezuela).

• Measurement: Earthquakes are recorded by seismographs, and magnitude is expressed on the Richter scale.

Other Disasters in the News

• Tsunamis: Giant ocean waves caused by undersea earthquakes, submarine landslides or volcanic eruptions. India's INCOIS runs the Next-Generation Tsunami Warning System with a sub-sea cable network in the Andaman–Sumatra subduction zone.

• Forest Fires: Caused by dry pre-monsoon conditions, dry fuel (pine needles and bamboo), strong winds and uncontrolled slash-and-burn (Jhum) cultivation (for example, in Lohit and Dzukou Valleys).

2. Water Pollution & Conservation

Sources of Water Pollution

• Industrial & Domestic Waste: Untreated sewage, chemicals, heavy metals and persistent pesticides (such as the banned organochlorine Aldrin, found in river ecosystems).

• Microplastics: Plastic waste and microplastics building up in rivers and wetlands (for example, the Brahmani River in Bhitarkanika).

• Organic & Ritual Waste: Pouring large amounts of organic material (such as milk and flowers) into rivers raises the Biological Oxygen Demand (BOD), lowering oxygen levels and killing aquatic life.

Waterborne Diseases

• Drinking or contact with polluted water causes diseases such as Cholera, Typhoid, Dysentery, Jaundice (Hepatitis) and gastroenteritis.

• Animals such as otters and river dolphins are bio-indicators — their presence shows a river is healthy.

Impacts on Water Security & Ecosystems

• Water Bankruptcy: Long-term over-pumping of groundwater and ecological damage can permanently reduce available water.

• Coral Bleaching: Marine heatwaves make corals expel the algae living in them (zooxanthellae), turning them white and threatening marine life.

Traditional Water Harvesting & Conservation

• Traditional Structures: Stepwells (Baolis), Johads (earthen check dams), man-made lakes (such as Pakhal Lake, built in 1213 CE) and Kole floodplain wetlands.

• Ramsar Sites: Wetlands of international importance, protected for flood control, groundwater recharge and biodiversity (for example, Tso Kar, Bakhira Lake, Hokersar and Vembanad).

• Public Trust Doctrine: The legal principle that rivers, lakes and other natural resources are held by the State in trust for the public and future generations (linked to Article 21 and Article 48A).

3. Renewable and Non-Renewable Energy Sources

Non-Renewable Energy (Fossil Fuels)

• Definition: Energy sources available in limited amounts that take millions of years to form from dead plants and animals deep inside the Earth.

• Coal: Dominates thermal power generation, accounting for nearly 79% of domestic energy supply. Types: Anthracite (highest quality), Bituminous, Lignite and Peat.

• Petroleum (Crude Oil): Refined into petrol, diesel, kerosene, LPG and aviation fuel.

• Natural Gas: The cleanest fossil fuel, made mostly of methane.

• Environmental Impact: Burning fossil fuels releases gases such as CO₂, SO₂ and NOₓ, causing global warming, acid rain and air pollution.

Renewable Energy (Clean Energy)

• Definition: Naturally replenished energy sources that produce little or no greenhouse gas.

• Solar Energy: Uses sunlight through photovoltaic cells. Key schemes: PM Surya Ghar Muft Bijli Yojana, PM-KUSUM (solar pumps for farmers) and floating solar projects (PM-SSY).

• Wind Energy: Uses wind turbines; managed digitally through platforms like WT-MARUT.

• Hydroelectric Power: Generates power from flowing or falling water (for example, the Sawalkote and Kirthai-II run-of-the-river projects on the Chenab). Hydrokinetic turbines make electricity from river currents without dams.

• Green Hydrogen & Green Ammonia: Made by electrolysis of water using renewable power; zero-emission fuels of the future.

• India's Clean Energy Targets: 60% non-fossil installed power capacity by 2035 (already above 52%) and Net Zero emissions by 2070.

4. Mountain Terrain & Lifestyle

Features of Mountain Terrain

• High altitude, steep rocky slopes, cold climate, low air pressure, less oxygen and a fragile ecological balance.

• Prone to landslides, avalanches, cloudbursts and Glacial Lake Outburst Floods (GLOFs).

Mountain Lifestyle, Farming & Livelihood

• Terrace Farming: Cutting step-like terraces into hill slopes to stop soil erosion and hold water for crops like rice, maize and vegetables.

• Shifting Cultivation (Jhum): Traditional slash-and-burn farming in the north-eastern hills, which needs careful control to prevent forest fires.

• Pastoral Nomads & Transhumance: Seasonal movement of herders (such as the Changpa (Khampa) nomads of Ladakh and the Gaddis and Bakarwals of the Himalayas) with livestock between summer pastures and winter valleys.

• Mountain Architecture: Houses with sloping wooden or stone roofs to shed snow and rain. Communities build natural structures such as Ru-Soam — cane and bamboo bridges made by the Lepcha community of Sikkim.

• High-Altitude Crops: Cold-tolerant crops like strawberries (for example, in Mizoram's Lawngtlai district) and wild Gucchi (morel) mushrooms in Himalayan coniferous forests.

5. Quick Revision Summary Table

Practise with MCQs

Test yourself with our Plants, Animals, Water Cycle and Environment MCQs, Pollution and Conservation MCQs and the environment current affairs sets for June 2026 and September 2026.

Free AISSEE Mock Test

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