Geography

Ocean Salinity Highest Salinity Sea in the World: Salinity of Oceans and Seas Compared The Red Sea, at about 40 parts per thousand, is the highest salinity sea in the world; the oceans and the other seas differ widely. Jun 202630 min read Ocean Salinity Desalination and the Impacts of Ocean Salinity: Sea Salt, Brine and Seawater Intrusion Desalination turns seawater into fresh water in Chennai and Lakshadweep; brine, sea salt and seawater intrusion show how ocean salinity affects the coast. Jun 202621 min read Ocean Salinity Sea Surface Temperature and Water Masses: Thermocline, T‑S Diagram and Ocean Fronts Sea surface temperature sets the layers of the ocean and fuels tropical cyclones; water masses carry their surface temperature and salinity into the deep. Jun 202619 min read Ocean Salinity Indian Ocean Currents and Salinity: Monsoon Drift, Arabian Sea and Bay of Bengal Indian Ocean currents reverse with the monsoon north of the equator and turn in a gyre to the south; the Arabian Sea is saltier than the… Jun 202618 min read Ocean Salinity Estuary: Meaning, Types, Salinity Gradient, Mangroves and Indian Examples An estuary is the tidal mouth of a river where fresh and salt water mix; its types, salinity gradient, mangroves and threats, with India's estuaries. Jun 202619 min read Ocean Salinity Indian Ocean Dipole, El Nino, Monsoon and Ocean Salinity in Climate The Indian Ocean Dipole, with El Nino, La Nina and the Walker circulation, helps decide India's monsoon, while salinity and a warming ocean shape its rain. Jun 202622 min read Cyclones Cyclones and Climate Change Cyclones and climate change for UPSC: warming seas, stronger and wetter storms, rapid intensification, the Arabian Sea shift, and what it means for India. Jun 20265 min read Cyclones Cyclone Disaster Management in India: Forecasting, Warnings and Response Cyclone disaster management in India begins with IMD's satellite and radar watch and four-stage warnings and ends with shelters and evacuation. Jun 202627 min read Ocean Salinity Thermohaline Circulation: Thermocline, Halocline, Deep Water Formation and AMOC Thermohaline circulation is the deep ocean circulation driven by density, set by heat and salt; cold, salty polar water sinks and drives the AMOC. May 202640 min read Ocean Salinity Salinity of Ocean Water: Sources, Factors and Distribution The salinity of ocean water averages about 35 parts per thousand. Its salts come mainly from rocks on land; evaporation, rain, rivers and ice make it… May 202624 min read Mid-Ocean Ridge: Formation, Features, Examples and Sea-Floor Spreading A mid-ocean ridge is the 65,000 km undersea mountain chain where plates part and new sea floor forms, as on the Mid-Atlantic Ridge and East Pacific Rise. May 202623 min read Cyclones List of Cyclones in Odisha from 1999 to 2024 and Major Cyclones in India The list of cyclones in Odisha from 1999 to 2024 gives each storm's wind speed and death toll beside the major cyclones of India's other coasts. May 202622 min read Cyclones Cyclone Impacts on India: Storm Surge and Coastal Vulnerability Cyclone impacts for UPSC: storm surge, coastal erosion, mangrove loss, agriculture and livelihood damage, and India's coastal-state vulnerability profile. May 202614 min read Cyclones Cyclone Season in India: Why Cyclones Peak in May and November Cyclone season in India has two peaks, May and November, because strong wind shear in the monsoon months of July and August stops most cyclones forming. May 202621 min read Cyclones Western Disturbances over India: Winter Rain and Snow Western Disturbances for UPSC: Mediterranean storms in the subtropical westerly jet bringing winter rain, Himalayan snow and Rabi-crop moisture to North India. May 202613 min read Cyclones Temperate Cyclone Formation, Stages and Polar Front Theory A temperate cyclone forms on the polar front, where polar and tropical air meet; it has fronts, grows in stages and reaches India as western disturbances. May 202623 min read Cyclones Stages of a Tropical Cyclone: Life Cycle from Disturbance to Dissipation A tropical cyclone grows from a low over warm sea into a named storm with an eye, then decays over land or cool water, in stages… May 202621 min read Cyclones Tropical Cyclogenesis: How Tropical Cyclones Form, Mechanism and Conditions Tropical cyclogenesis for UPSC: the six conditions, seed disturbances, the WISHE feedback engine, warm-core growth, and the Genesis Potential Index. May 202615 min read Cyclones Bay of Bengal and Arabian Sea Cyclones, Global Distribution and Basins The Bay of Bengal produces about four times as many cyclonic storms as the Arabian Sea, and deadlier ones, owing to its warm water and low,… May 202611 min read Cyclones Cyclone Classification, Naming and Tracking Cyclone classification for UPSC: IMD seven-tier wind-speed scale, Saffir-Simpson cross-reference, thirteen-nation naming panel, and RSMC New Delhi tracking. May 202615 min read Cyclones Tropical Cyclone: Meaning, Formation, Structure and Classification A tropical cyclone forms over warm seas and runs on the heat of condensing vapour; it has a calm eye and a violent eyewall, and IMD… May 202635 min read Indian Drainage System Indian Rivers: Floods, Pollution, Conservation and Climate Change Indian rivers explained for UPSC: floods, river pollution, the Namami Gange programme, conservation, and how climate change reshapes glacier-fed flows. May 202617 min read Indian Drainage System River Linking and Inter-State Water Disputes River linking and inter-state water disputes for UPSC: how Indian rivers drive irrigation, hydropower, the NRLP 30 links, and six dispute tribunals. May 202615 min read Indian Drainage System River Landforms: Erosional and Depositional Features, Deltas and Estuaries Erosional and depositional river landforms for UPSC: gorges, waterfalls, alluvial fans, meanders, oxbow lakes, deltas and estuaries, with Indian examples. May 202613 min read Indian Drainage System West Flowing Rivers of India: Narmada, Tapti, Luni and Inland Drainage West flowing rivers of India for UPSC: why the Narmada and Tapti run west through rift valleys and form estuaries, and why the Luni ends in… May 202615 min read Indian Drainage System Kaveri River and Krishna River: Course, Tributaries, Dams and Water Disputes Kaveri River and Krishna River: Origin, course, tributaries, dams such as Nagarjuna Sagar and Mettur, and the Cauvery and Krishna water disputes. May 202632 min read Indian Drainage System Godavari River and Mahanadi River: East-Flowing Peninsular Rivers The Godavari River and the Mahanadi River cross the Deccan to the Bay of Bengal; their basins hold Hirakud, Polavaram and two inter-state water disputes. May 202634 min read Indian Drainage System Brahmaputra River: Tsangpo, Braiding, Assam Floods Brahmaputra river for UPSC: how the Yarlung Tsangpo becomes the Brahmaputra at Sadiya, the braided Assam floods, Majuli island, tributaries and the Barak. May 202615 min read Indian Drainage System Ganga Delta and Sundarbans: Geomorphology and Cultural Significance Ganga delta geomorphology for UPSC: meanders and oxbows on the Indo-Gangetic plain, the world's largest delta, the Sundarbans, and the Farakka split. May 202616 min read Indian Drainage System Ganga River System: Origin, Tributaries, Yamuna and the Ganga Basin The Ganga river system begins at Gangotri and gathers the Yamuna, Ghaghara, Gandak, Kosi and Son before it reaches the Bay of Bengal. May 202643 min read Indian Drainage System Indus River System and Indus Waters Treaty (1960) Indus River System for UPSC: the main Indus, the five Punjab tributaries (Jhelum, Chenab, Ravi, Beas, Sutlej), and the 1960 Indus Waters Treaty split. May 202616 min read Indian Drainage System Himalayan Rivers: Characteristics and Features of the Himalayan River System Himalayan rivers are fed by snow and rain, flow all year, cut deep gorges through rising mountains and build the northern plains. May 202632 min read Indian Drainage System Antecedent Drainage and Superimposed Drainage in India: Evolution and River Capture Antecedent and superimposed drainage, the Indo-Brahma river and river capture explain how Indian rivers cross mountains or change basins. May 202623 min read Indian Drainage System Factors Controlling Drainage Patterns Factors that control drainage patterns explained for UPSC: how geology, relief, rock type, tectonics and rainfall shape Indian rivers like the Damodar. May 202611 min read Indian Drainage System Types of Drainage Patterns with Examples The types of drainage patterns, from dendritic and trellis to radial and centripetal, show the rock beneath a river, with Indian examples of each. May 202619 min read Indian Drainage System Drainage System of India: River Basins, Himalayan and Peninsular Rivers Drainage system of India explained for UPSC: what a river basin, catchment and watershed mean, and how Himalayan, Peninsular and inland rivers differ. May 202611 min read Green Revolution Farmer Producer Organisations (FPOs) and Agricultural Policy in India Farmer producer organisations (FPOs) for UPSC: GR 2.0 policy architecture and FPO vehicle via the 10,000 FPO Scheme 2020, NMSA, PM‑KUSUM, NFSM, PMFBY and KCC. May 202615 min read Green Revolution Precision, Digital and Biofortified Agriculture Precision and digital agriculture for UPSC: precision farming, AgriStack digital agriculture, and biofortified crops like Golden Rice and Dhanashakti pearl millet. May 202614 min read Green Revolution Climate-Smart Agriculture in India: NICRA and the FAO Pillars Climate-Smart Agriculture for UPSC: FAO three pillars, NICRA by ICAR‑CRIDA, climate-resilient varieties, CCAFS, GACSA, and India's monsoon adaptation. May 202612 min read Green Revolution Natural and Organic Farming in India: ZBNF, PKVY and Sustainable Agriculture Sustainable agriculture for UPSC: conservation farming, NPOP organic under APEDA, PKVY, and natural-farming models SPNF, BPKP and APCNF. May 202614 min read Green Revolution Green Revolution 2.0: Meaning, Need and Features Green Revolution 2.0 for UPSC: productivity-to-sustainability pivot, four drivers, GR 1.0 vs 2.0 comparison, six objectives, and the Evergreen Revolution. May 202613 min read Green Revolution Negative Impact of the Green Revolution: Social, Economic and Environmental Effects Negative impact of the Green Revolution for UPSC: socio-economic and environmental critique of GR 1.0, groundwater depletion, stubble burning, and the bridge to GR 2.0. May 202614 min read Green Revolution Impact of the Green Revolution in India: Institutions and Regional Effects Impact of the Green Revolution in India for UPSC: FCI, CACP/MSP and NABARD credit; why the Punjab-Haryana wheat belt led while eastern India and dryland regions… May 202614 min read Green Revolution Green Revolution Technological Package Green Revolution technological package for UPSC: HYV seeds, fertilisers, irrigation, mechanisation, and credit as one integrated farm input system in India. May 20269 min read Green Revolution Origins of the Green Revolution: Norman Borlaug, M. S. Swaminathan and HYV Seeds Origins of the Green Revolution for UPSC: Borlaug's CIMMYT dwarf wheat, IRRI's IR8 rice, Swaminathan's IARI adaptation, and India's 1966 HYV Programme launch. May 202610 min read Green Revolution Indian Agriculture Before the Green Revolution: Famines, PL‑480 and the Food Crisis Indian agriculture before the Green Revolution for UPSC: India's pre-1966 food crisis, the Bengal famine, PL‑480 wheat imports, the Bihar drought, and the seed-fertiliser pivot. May 202611 min read Indian Agriculture Colour Revolutions in Indian Agriculture, Rural Economy and Farming Models Indian agriculture colour revolutions for UPSC: Green, White, Blue, Yellow plus NABARD rural credit, agrarian distress, FPOs and contemporary farm models. May 202610 min read Indian Agriculture Dryland Farming in India: Meaning and Examples Dryland farming and sustainable agriculture for UPSC: rainfed crops, ICAR‑CRIDA, NMSA, NICRA 2011, NPOP organic farming, Sikkim, ZBNF and climate change. May 202610 min read Indian Agriculture Agricultural Marketing in India: APMC, Land Reforms and Farm Policies Agricultural marketing in India for UPSC: APMC mandis, MSP regime, CACP, FCI procurement, land reforms from zamindari abolition to land ceiling, plus PM‑KISAN. May 202611 min read Indian Agriculture Indian Agriculture: Inputs, Technology and Productivity Indian agriculture inputs for UPSC: HYV seeds, SRR, NPK 4:2:1 imbalance, Soil Health Card 2015, Kisan Credit Card 1998, and the per-hectare yield gap. May 202611 min read Indian Agriculture Irrigation in India: Sources, PMKSY and Problems Irrigation in India draws mainly on tube-wells, canals and tanks. PMKSY funds its growth; falling groundwater and waterlogging are its chief problems. May 202641 min read Indian Agriculture Horticulture, Livestock and Fisheries in India Horticulture, livestock and fisheries for UPSC: India allied agricultural sectors, MIDH, 20th Livestock Census, DAHD, PMMSY, NFDB and the Blue Revolution. May 202612 min read Indian Agriculture Plantation Crops in India: Tea, Coffee, Rubber Plantation crops in India, chiefly tea, coffee and rubber, grow in distinct regions on estates and small holdings, each with its own commodity board. May 202635 min read Indian Agriculture Commercial Crops in India: Cotton, Sugarcane, Jute Cotton, sugarcane, oilseeds, and jute for UPSC: black-soil cotton, sugarcane FRP, Yellow Revolution oilseeds, and jute, the golden fibre of the delta. May 202610 min read Indian Agriculture Millets and Pulses in India: Types, Producing States and Policy Millets and pulses in India grow mostly on rainfed drylands, led by Rajasthan for bajra, Maharashtra for jowar and Madhya Pradesh for gram and all pulses. May 202633 min read Indian Agriculture Rice and Wheat Production in India: States, Cultivation and MSP Rice and wheat production in India runs through two seasons, kharif rice and rabi wheat, often on one field, with both bought at MSP for the… May 202628 min read Indian Agriculture Cropping Seasons in India: Kharif, Rabi, Zaid and Agricultural Regions Cropping seasons in India for UPSC: agro-climatic regions, the three cropping seasons (Kharif, Rabi, Zaid), farming systems, and cropping-pattern change. May 202610 min read Indian Agriculture Land Use Pattern in India and the Physical Factors of Agriculture The land use pattern in India follows a nine-fold classification, and relief, monsoon rainfall, soils and water decide how intensively the land is farmed. May 202630 min read Indian Soils Soil Erosion in India: Types, Causes, Degradation and Conservation Soil erosion in India by water, wind and waves, its causes and effects, wider land degradation, and the conservation methods and schemes that check it. May 202634 min read Indian Soils Soil Fertility and Productivity in India Soil fertility vs productivity for UPSC: the NPK and micronutrient profile, pH and CEC, the soil-climate-crop link, and the Soil Health Card scheme. May 202612 min read Indian Soils Peaty Soil and Marshy Soil in India, Kari Soil of Kerala and Wetlands Peaty soil forms where waterlogging slows the decay of dead plants; in India it is found in north Bihar, the Tarai, the east coast and Kerala's… May 202619 min read Indian Soils Saline and Alkaline Soils in India: Causes, Types and Reclamation Saline and alkaline soils in India form where salts or sodium build up in poorly drained land, and gypsum, drainage and salt-tolerant crops reclaim them. May 202628 min read Indian Soils Mountain Soil and Forest Soil in India: Features, States and Crops Mountain soil, or forest soil, is fertile in valleys and thin and acidic on upper slopes; it carries India's tea and coffee and is easily lost… May 202619 min read Indian Soils Arid Soil in India (Desert Soil): Features, Formation, States and Crops Arid soil (desert soil) in India, where it is found, its features, kankar and salts, the crops it grows, the Indira Gandhi Canal and desertification. May 202617 min read Indian Soils Laterite Soil and Red Soil in India: Formation, Difference and Crops Laterite soil forms under heavy rain, red soil under low rainfall. Both are red from iron, and they differ in leaching, where they occur and their… May 202616 min read Indian Soils Alluvial Soil in India: Khadar and Bhangar Difference, Features and Map Alluvial soil, laid down by rivers, covers about 40 per cent of India; its two ages, khadar and bhangar, differ in position, kankar and fertility. May 202615 min read Indian Soils Types of Soil in India: Formation and Classification Types of soil in India for UPSC: soil definition, the five soil-forming factors, profile horizons, and the ICAR‑USDA classification of Indian soils. May 20268 min read Climate of India Koppen Climate Classification of India and Thornthwaite The Koppen climate classification sorts climates into five lettered groups and India into eight regions; Thornthwaite weighs rain against evaporation. May 202630 min read Climate of India Distribution of Rainfall in India: Temperature, Pressure, Winds and Local Winds The distribution of rainfall in India runs from over 1,000 cm in Meghalaya to under 10 cm in the Thar; temperature, pressure and winds explain it. May 202628 min read Climate of India Monsoon Variability in India: Floods, Droughts, Climate Change and Sector Impacts Climate of India for UPSC: monsoon variability, drought, flood, cyclone and heat wave hazards, the IPCC AR6 signal, and the NAPCC, NDC and Net Zero 2070… May 202615 min read Climate of India Seasons of India with Months (Winter, Summer, Monsoon, Retreating) The four seasons of India, from the cold weather to the retreating monsoon, each bring their own winds and rain; the old calendar has six ritus. May 202619 min read Climate of India Theories of Monsoon: Onset, Burst, Break and Withdrawal of Monsoon The monsoon reaches Kerala around 1 June, and the withdrawal of monsoon begins in the north-west around 17 September; three theories explain its timing. May 202637 min read Climate of India Indian Monsoon: Pressure, Winds and Jet Streams Indian monsoon pressure, winds and jet streams for UPSC: pressure belts, ITCZ, monsoon trough, jet streams (STWJ, TEJ), ENSO, IOD, MJO teleconnections, Coriolis force. May 202616 min read Climate of India Climate of India: Factors That Control It Climate of India foundation for UPSC: tropical monsoon character, latitudinal factor (Tropic of Cancer), altitude (Himalayan barrier), distance from sea,. May 202617 min read Drainage Patterns of India: Geometry, Genesis, and River Systems A drainage pattern is the geometric arrangement formed by a river and its tributaries across a landscape, reflecting the underlying lithol May 202614 min read Western Disturbances and India's Winter Weather Systems A Western Disturbance (WD) is an extratropical synoptic-scale low-pressure system that originates over the Mediterranean May 202612 min read Biodiversity Hotspots Biodiversity Conservation in India: In Situ and Ex Situ Methods, Laws and Conventions Biodiversity conservation explained: in situ and ex situ methods, biosphere reserves, the Wildlife and Biological Diversity Acts, CBD, Ramsar and CITES. May 202620 min read Biodiversity Hotspots Sundaland Hotspot in India, Nicobar Islands and Biogeographic Zones Why the Sundaland hotspot in India covers only the Nicobar Islands, with their wildlife, the Great Nicobar project and India's ten biogeographic zones. May 202627 min read Biodiversity Hotspots Gadgil and Kasturirangan Reports: Western Ghats ESZ Western Ghats threats and ESZ debate for UPSC: Gadgil 2011 vs Kasturirangan 2013, state-level pushback, Wayanad 2024 landslide, way forward. May 202612 min read Biodiversity Hotspots Western Ghats Biodiversity Hotspot The Western Ghats run 1,600 km through six States and, with Sri Lanka, form one biodiversity hotspot rich in endemic plants, frogs, fishes and mammals. May 202640 min read Biodiversity Hotspots Indo-Burma Hotspot: Region, North-East India, Species and Threats The Indo-Burma hotspot runs from north-east India to Vietnam; it is rich in species found nowhere else, yet only 5 per cent of its vegetation survives. May 202630 min read Biodiversity Hotspots Himalayan Biodiversity Hotspot: Extent, Endemism, Threats Himalayan Biodiversity Hotspot for UPSC: Eastern and Western Himalaya extent, altitudinal zonation, endemic flora, snow leopard, and climate-change threats. May 202614 min read Biodiversity Hotspots Biodiversity Hotspots in India and the World Biodiversity hotspots are regions rich in endemic plants that have lost most of their vegetation; the world has 36, and India shares four of them. May 202629 min read Biodiversity Hotspots Biodiversity: Levels, India's Status and BD Act 2002 Biodiversity for UPSC: four levels (genetic, species, ecosystem, functional), endemic and keystone species, India mega-diverse status, BD Act 2002. May 202612 min read Forest Types of India: Natural Vegetation, Champion and Seth Classification and Forest Cover The forest types of India fall into five main types and sixteen Champion and Seth type groups; ISFR 2023 puts forest cover at 21.76 per cent. May 202640 min read Plate Tectonics: Continental Drift, Sea-Floor Spreading, Plate Boundaries and Mantle Plumes Plate tectonics grew from continental drift and sea-floor spreading, and it explains plate boundaries, mantle plumes and the rise of the Himalaya. May 202641 min read Indian Monsoon Indian Monsoon and Climate Change: Mission Mausam, Cloudbursts Indian monsoon and climate change for UPSC: IPCC AR6 climate-change projections, Mission Mausam 2024, cloudbursts mechanism, NDMA mitigation, PMFBY 2016, PMKSY, SASCOF. May 202615 min read Indian Monsoon Northeast Monsoon, Retreating Monsoon and Regional Variation of Rainfall in India The northeast monsoon gives Tamil Nadu nearly half its yearly rain from October to December, while the retreating monsoon leaves most of India dry. May 202623 min read Indian Monsoon Indian Monsoon: Mechanism of Monsoon, ITCZ, Jet Streams and Drivers The Indian monsoon is driven by land heating, the ITCZ, the Coriolis force and the jet streams; El Niño, the IOD and the MJO decide how… May 202632 min read Earthquakes Earthquake Disaster Management in India, NDMA Guidelines and Earthquake-Resistant Construction Earthquake disaster management in India rests on the Disaster Management Act, 2005, the NDMA guidelines of 2007, safe building codes and quick response. May 202629 min read Earthquakes Seismic Zones of India: BIS IS 1893, Hazard Mapping and the Himalayan Gaps India's seismic zones explained: the BIS IS 1893 four-zone map, which regions fall in Zone V, the Himalayan seismic gaps, and how microzonation refines earthquake hazard… May 202614 min read Earthquakes How Earthquakes Occur: Mechanism, Plates and Seismic Waves Learn how earthquakes occur: fault rupture, elastic rebound, the three plate boundaries, P and S waves, and how Richter and moment magnitude differ. May 202618 min read Indian Soils Black Soil in India: Regur Soil, Formation, Characteristics, Crops and the Deccan Trap Black soil (regur) in India: Deccan Trap origin, clay and cracking, moisture, nutrients, states, crops and how it differs from red and laterite soil. May 202617 min read Soil Liquefaction: Mechanism, Conditions and Susceptibility Soil liquefaction is the phenomenon in which saturated, loose, granular soils, principally fine sands, silty sands, and young alluvium, lose nearly all of May 202621 min read ENSO El Nino Modoki, ENSO Teleconnections and Global Climate Impacts Teleconnections carry El Nino and La Nina far beyond the Pacific. El Nino Modoki, the Indian Ocean Dipole and warming change how strong their effects are. May 202629 min read ENSO Effect of El Nino in India on Monsoon, Farms and Economy The effect of El Nino in India is usually a weaker monsoon and more drought; La Nina brings more rain, and the Indian Ocean Dipole can… May 202620 min read ENSO ENSO: Pacific Ocean-Atmosphere Coupling, El Niño-La Niña Cycle, Mechanism and Dynamics ENSO for UPSC: how Pacific trade winds, the Walker Circulation, Bjerknes feedback, and the Nino 3.4 SST index drive the El Nino and La Nina cycle. May 202619 min read Air Masses: Types, Source Regions, Fronts and Frontogenesis Air masses take the temperature and moisture of the region where they form; where two unlike air masses meet, a front forms and the weather changes. May 202619 min read Glaciers of India: Major Glaciers, Rivers and Retreat Glaciers of India for UPSC: the Siachen and Gangotri glaciers, the rivers they feed, why they are India's water towers, and their retreat under climate change. May 20268 min read Global Warming: Meaning, Causes, Effects and Control Measures Global warming is the human-driven rise in Earth's temperature, caused by greenhouse gases and met by a global response from Kyoto to Paris. Dec 202550 min read Roman Geographers and Their Contributions: Strabo, Mela, Pliny and Ptolemy Strabo, Mela, Pliny and Ptolemy, the leading Roman geographers, described and measured the known world and recorded what Rome knew of India. Jan 202433 min read Fundamental Concepts of Geomorphology: Meaning, Processes and Landform Evolution Geomorphology studies how landforms form and change. Weathering, mass movement, erosion and the landform models of Davis, Penck and King are explained. Nov 202345 min read Processes of Erosion: Corrasion, Corrosion, Attrition and Hydraulic Action Rivers, glaciers, waves and wind erode rock by hydraulic action, corrasion, attrition and corrosion, and a third of India's mainland coast is eroding. Nov 202313 min read Railway Zones in India: List of 18 Zones, Headquarters and Divisions India has 18 railway zones, each run from its own headquarters and divided into divisions. South Coast Railway became the 18th zone on 1 June 2026. Nov 202317 min read Heat Budget of the Earth: Insolation, Albedo and Temperature Inversion The heat budget of the earth balances incoming insolation against outgoing terrestrial radiation, and it governs how temperature is spread over the earth. Apr 201939 min read Physical Geography Terms and Definitions: A to Z Glossary Each physical geography term, from the earth's interior and landforms to climate, oceans, soils and maps, is defined in plain words beside related terms. Apr 201999 min read Pacific Ring of Fire: Location, Map, Volcanoes and Earthquakes The Pacific Ring of Fire runs round the Pacific Ocean through more than two dozen countries; subduction at its trenches causes its earthquakes and volcanoes, and… Mar 201921 min read Global Distribution of Soils: World Soil Types, the 12 Soil Orders and Soil Zones Soil orders are the 12 broadest groups of USDA soil taxonomy. Their global distribution follows climate, from frozen Gelisols to tropical Oxisols. Feb 201933 min read Soil Profile and Soil Horizons: Layers of Soil, Diagram and the Solum A soil profile is the vertical section of soil from the surface to the bedrock, made up of six layers, the O, A, E, B, C… Feb 201913 min read Leaching of Soil: Meaning, Process, Eluviation and Illuviation Leaching is the washing of soluble minerals down through the soil by water. It forms laterite, drains nutrients and carries nitrate into groundwater. Feb 201915 min read Soil Formation: Genesis of Soil, Its Five Factors and Soil-Forming Processes Soil formation starts with weathered rock, is controlled by five factors (CLORPT) and works through processes that build horizons and soil types. Feb 201933 min read Time Zones and the International Date Line: Longitude, UTC and IST Time zones follow longitude at four minutes a degree; the International Date Line changes the date, and India keeps one clock, IST, at 82° 30′ E. Feb 201918 min read Theory of Isostasy: Meaning, Airy and Pratt Models and Isostatic Adjustment Isostasy is the balance of the crust floating on the denser mantle, explained by the Airy and Pratt models; loads of ice or rock make land… Nov 201816 min read Hot Deserts of the World: Why They Form at 20 to 30 Degrees Latitude Hot deserts form at 20 to 30 degrees because air sinks there in the Hadley cell; cold currents make the western coasts of continents the driest. Nov 201821 min read