Daily Prelims MCQs - Sci-Tech, Environment and Geography - 23rd August 2025
- TPP
- Aug 24
- 19 min read
Welcome to The Press Pad Daily UPSC Prelims MCQs – 23rd August 2025 (Science & Technology, Environment, and Geography focus).This carefully curated set of multiple-choice questions (MCQs) is designed to help aspirants practice high-probability topics for UPSC Prelims 2025 and other competitive exams like State PCS, CDS, NDA, and CAPF.
Today’s quiz covers:
Indian Ocean Dipole (IOD) and monsoon linkages
Dial-up Internet history and its evolution
Tripledemic viruses (COVID-19, Flu, RSV)
Neutron stars and gravitational waves
PM-WANI scheme vs BharatNet
Newton’s Third Law (airfoil, spinning ball, jet thrust)
Artemis Accords & Outer Space Treaty
Jellyfish proliferation & marine ecology
Whale strandings on Indian coasts
ENSO (El Niño, La Niña, Neutral phase)
Regional Winds (Santa Ana, Chinook, Mistral, Bora)
Green Climate Fund (GCF) under UNFCCC
These MCQs are framed in UPSC-standard format with detailed explanations, tables, and comparison charts to ensure concept clarity + quick revision value.
Click Here to read the Monthly Current Affairs Pointers (CAP).
QUESTION 1
With reference to the Indian Ocean Dipole (IOD), consider the following statements:
It represents a recurring climate phenomenon confined to the Indian Ocean.
In its positive phase, cooler waters shift towards the eastern Indian Ocean near Australia.
The IOD has no significant role in influencing regional weather events.
How many of the statements given above are correct?
(a) Only one
(b) Only two
(c) All three
(d) None
Answer (a)
Explanation:
The Indian Ocean Dipole (IOD) is a climate pattern that develops in the Indian Ocean, similar in influence to the El Niño–Southern Oscillation (ENSO) in the Pacific. It is identified by differences in sea surface temperatures (SSTs) between the western and eastern Indian Ocean. Hence, Statement 1 is correct.
In the positive phase of IOD, warmer waters accumulate in the western Indian Ocean (near Africa), while upwelling of cooler, deep waters takes place in the eastern Indian Ocean (near Indonesia and Australia). This situation reverses in the negative phase. Hence, Statement 2 is not correct.
The IOD strongly impacts local and regional weather systems. For example:
Positive IOD → heavy rainfall in East Africa, drought-like conditions in Australia.
Negative IOD → the reverse, with wetter conditions in Australia and drier conditions in East Africa.
The associated sea-level variations can even increase the risk of coastal flooding. Hence, Statement 3 is not correct.
In June, the sea surface temperatures in the equatorial Pacific Ocean were observed in the range of 0–0.4°C, which reflected ENSO-neutral conditions (meaning neither El Niño nor La Niña was active). While this relates to ENSO, it helps illustrate how ocean-atmosphere systems are monitored globally in parallel.
Indian Ocean Dipole (IOD): Positive vs Negative
Feature | Positive IOD | Negative IOD |
Sea Surface Temperature (SST) | Warmer waters in Western Indian Ocean (near Africa). | Warmer waters in Eastern Indian Ocean (near Indonesia & Australia). |
Upwelling (cold water rising to surface) | Enhanced near Indonesia/Australia, leading to cooler waters there. | Enhanced near East Africa, leading to cooler waters there. |
Rainfall in East Africa | Heavy rainfall, floods common. | Drier conditions, risk of drought. |
Rainfall in Australia/Indonesia | Drought-like conditions, reduced rainfall. | Wet conditions, floods possible. |
Indian Monsoon Impact | Often strengthens monsoon in India (though impact varies). | Can weaken monsoon in India. |
Sea Level Change | Higher sea levels near East Africa, lower near Indonesia. | Higher sea levels near Indonesia, lower near East Africa. |
Global Relevance | Can counter or amplify El Niño impacts. | Can counter or amplify La Niña impacts. |
QUESTION 2
With reference to dial-up internet, consider the following statements:
It allowed internet access through a computer’s modem connected to a home telephone line (landline).
Connecting to the internet on dial-up was marked by distinct beeps and digital screeching sounds.
Its origin is linked with exchanging messages and files via the UNIX-to-UNIX copy protocol (UUCP).
Which of the statements given above is/are correct?
(a) 1 and 2 only
(b) 2 only
(c) 3 only
(d) 1, 2 and 3
Answer (d)
Explanation:
CompuServe was among the first to offer commercial dial-up services (1979).
AOL (America Online) popularised dial-up internet in the early 1990s; it became a household brand in the US.
However, by 1995, dial-up started losing ground to cable internet, which offered far higher speeds using existing cable TV lines.
Recently, AOL announced the permanent shutdown of its last remaining dial-up subscribers, formally ending the service that once introduced millions to the internet.
Statement 1 is Correct: Dial-up internet was an early method of connecting to the internet using a modem (device that modulates and demodulates signals) and a telephone landline. The speed was extremely slow by today’s standards—typically 56 kilobits per second (kbps) or less.
Statement 2 is Correct: When users connected to the internet, the modem generated distinctive beeps, hisses, and screeches. These were actually the handshake signals exchanged between modems to establish the connection.
Statement 3 is Correct: The roots of dial-up internet go back to Usenet (1979), created by two graduate students at Duke University (US). It enabled exchange of messages and files between computers using UUCP (UNIX-to-UNIX Copy Protocol), which allowed remote UNIX systems to communicate.
QUESTION 3
NVS-03, NVS-04, and NVS-05 satellites are associated with which of the following?
(a) Navigation services
(b) Communication services
(c) Weather-related services
(d) Lunar satellites
Answer (a)
Explanation:
In ISRO’s 100th launch, NVS-02 was sent into orbit (Jan 2025). However, due to a technical glitch in orbit-raising manoeuvres, it could not be placed in its correct orbit. The upcoming NVS-03, NVS-04, and NVS-05 will strengthen NavIC services, ensuring better positioning accuracy for civilian and strategic applications.
NVS-03, NVS-04, and NVS-05 are part of India’s Regional Navigation Satellite System (IRNSS), also popularly known as NavIC (Navigation with Indian Constellation).
According to the Union Minister of State for Space (Dr. Jitendra Singh), ISRO plans to launch all three satellites by next year:
NVS-03 → targeted for launch by year-end.
NVS-04 and NVS-05 → planned subsequently, each with a gap of ~6 months.
About IRNSS / NavIC
IRNSS was designed as a 7-satellite constellation to provide precise navigation services across the Indian landmass and up to 1,500 km around India’s borders.
Till date, 11 satellites have been launched to maintain and upgrade the constellation.
Two satellites failed to achieve their intended orbit.
Global Navigation Satellite Systems (GNSS) – Quick Comparison
System | Country/ Region | No. of Satellites (Operational) | Coverage | Accuracy (civilian use) | Key Features |
NavIC (IRNSS) | India | 7 core + backups (regional) | India + 1,500 km around | ~5–20 m | Regional focus, dual-frequency (L5, S-band), independent for strategic needs |
GPS | USA | ~31 | Global | ~5–10 m | Oldest, widely used globally, controlled by US military |
GLONASS | Russia | ~24 | Global | ~5–10 m | Provides redundancy to GPS, military-grade precision for Russia |
BeiDou | China | ~35 | Global | ~2–5 m | Offers both regional & global coverage, strong in Asia-Pacific |
Galileo | European Union | ~26 (full 30 planned) | Global | <1 m (with paid services) | Civilian-controlled, very high accuracy |
QZSS | Japan | 4 (target 7) | Regional (Asia-Pacific) | ~1–2 m | Complements GPS, enhances accuracy in urban & mountainous terrain |
QUESTION 4
The term ‘tripledemic’ is used in public health to describe the simultaneous spread of three major respiratory viruses. Which of the following is not part of this group?
(a) COVID-19
(b) Influenza
(c) Respiratory syncytial virus
(d) Respiratory adenoviruses
Answer (d)
Explanation:
In the UK, health experts warned of a possible tripledemic during autumn–winter seasons due to rising cases.
India, with similar seasonal spikes in flu and respiratory infections, may also face such challenges in healthcare management.
The word tripledemic comes from combining triple (three) + epidemic.
It refers to the parallel circulation of three respiratory viruses:
COVID-19 (caused by SARS-CoV-2 virus)
Influenza (flu virus)
Respiratory Syncytial Virus (RSV)
These three viruses are grouped together because:
They tend to spike during colder months.
They affect similar vulnerable groups — especially elderly, children, and people with chronic illnesses.
They put pressure on healthcare systems due to overlapping surges in hospitalisations.
Respiratory adenoviruses, though capable of causing respiratory illness, are not part of the tripledemic definition.
Tripledemic Viruses – Quick Comparison
Feature | COVID-19 | Influenza (Flu) | Respiratory Syncytial Virus (RSV) |
Causative Agent | SARS-CoV-2 (Coronavirus) | Influenza virus (Types A & B) | Respiratory Syncytial Virus (Paramyxovirus family) |
Transmission | Droplets, aerosols, surfaces | Droplets, aerosols, surfaces | Droplets, close contact, surfaces |
Incubation Period | 2–14 days (avg. 5) | 1–4 days (avg. 2) | 2–8 days |
Seasonal Peak | Waves, but often winter surges | Winter & early spring | Winter months |
High-Risk Groups | Elderly, co-morbid patients, immunocompromised | Elderly, infants, people with chronic illnesses | Infants, young children, elderly, those with weak immunity |
Typical Symptoms | Fever, cough, fatigue, breathlessness, loss of smell/taste | Fever, chills, sore throat, cough, muscle pain | Wheezing, severe cough, breathing difficulty (esp. in infants) |
Impact on Healthcare | Pandemic-level surges, ICU load | Annual flu epidemics, high absenteeism | Hospitalisations in infants & elderly, burden on pediatric care |
QUESTION 5
With reference to neutron stars, consider the following statements:
They are extremely dense stellar remnants formed after the supernova explosion of a massive star.
In binary systems, they lose energy continuously through gravitational wave emission until they collide and merge.
Which of the statement(s) given above is/are correct?
(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2
Answer (c)
Explanation:
Statement 1 is Correct:
A neutron star is a superdense astrophysical object formed when a massive star (8–25 times the mass of the Sun) ends its life in a supernova explosion (violent stellar death).
The star’s core collapses, protons and electrons combine into neutrons, creating a compact object of about 10–20 km radius but with a mass up to 1.4–2 times the Sun.
Density: ~10¹⁷ kg/m³ (a teaspoon of neutron star matter weighs billions of tons).
Statement 2 is Correct:
Neutron stars are often found in binary systems (orbiting pairs).
Due to Einstein’s General Relativity, such systems lose orbital energy by emitting gravitational waves (ripples in spacetime).
Over time, the stars spiral closer, eventually colliding and merging in an explosive event called a kilonova.
Significance of Neutron Star Mergers:
Source of gravitational wave detections (e.g., LIGO, Virgo).
Create extreme conditions allowing formation of heavy elements like gold, platinum, uranium through the r-process (rapid neutron capture process).
Provide insights into physics of matter under ultra-high densities.
Feature | White Dwarf | Neutron Star | Black Hole |
Origin | Remnant of a low/medium-mass star (< 8 solar masses) after shedding outer layers (planetary nebula stage). | Core-collapse of a massive star (8–25 solar masses) after supernova. | Collapse of very massive stars (> 25 solar masses) beyond neutron degeneracy limit. |
Mass | Up to ~1.4 solar masses (Chandrasekhar limit). | ~1.4–2 solar masses (Tolman–Oppenheimer–Volkoff limit). | Can be several solar masses to billions (supermassive black holes). |
Radius | ~5,000–10,000 km (similar to Earth). | ~10–20 km (city-sized). | Radius defined by event horizon (Schwarzschild radius). |
Density | ~10⁹ kg/m³ | ~10¹⁷ kg/m³ (teaspoon weighs billions of tons). | Infinite (theoretically, singularity at core). |
Composition | Mostly carbon + oxygen nuclei in a sea of degenerate electrons. | Almost entirely neutrons (neutron-degenerate matter). | No matter state; spacetime curvature prevents escape of light. |
Support Against Gravity | Electron degeneracy pressure. | Neutron degeneracy pressure (and nuclear forces). | No known force – complete collapse under gravity. |
Phenomena | Faint luminosity, slowly cooling. | Pulsars (rotating neutron stars emitting beams of radiation), magnetars (highly magnetised). | Accretion disks, relativistic jets, gravitational lensing. |
Detectability | White glow, UV emissions. | X-rays, radio pulses, gravitational waves (from mergers). | Indirect only (effects on nearby matter, gravitational waves, event horizon imaging). |
QUESTION 6
What is the primary aim of the PM-WANI (Prime Minister Wi-Fi Access Network Interface) scheme?
(a) To promote exclusive high-speed broadband connections for government offices.
(b) To replace all existing mobile networks with a single government-run network.(c) To provide free Wi-Fi in public places nationwide.
(d) To provide free rechargeable points for cellphones in public places across the country.
Answer (c)
Explanation:
The PM-WANI scheme was launched by the Government of India to expand internet connectivity through public Wi-Fi networks.
It seeks to provide affordable and easy access to broadband internet in public spaces such as railway stations, bus stands, markets, educational institutions, and other crowded areas.
The scheme works by setting up a network of Public Data Offices (PDOs) and Public Data Office Aggregators (PDOAs) that provide Wi-Fi services without requiring heavy licensing requirements.
Key Features of PM-WANI:
Free or very low-cost Wi-Fi access for citizens.
Promotes Digital India vision by enhancing last-mile internet connectivity.
Boosts digital inclusion → especially useful for students, travelers, and small businesses.
Encourages startups and local entrepreneurs to set up PDOs with minimal regulatory burden.
BharatNet vs PM-WANI
Feature | BharatNet | PM-WANI |
Launched by | Department of Telecommunications (DoT) | Department of Telecommunications (DoT) |
Objective | Provide high-speed broadband connectivity to all Gram Panchayats (rural areas) using optical fiber. | Provide public Wi-Fi access in urban & rural areas through a decentralized, market-driven model. |
Coverage Focus | Rural India (last-mile broadband to 2.5 lakh Gram Panchayats). | Public places (railway stations, markets, schools, bus stands, etc.) nationwide. |
Infrastructure | Optical Fiber Cable (OFC) network laid under Universal Service Obligation Fund (USOF). | Wi-Fi hotspots created through Public Data Offices (PDOs) and Aggregators (PDOAs), no heavy licensing. |
Business Model | Government-funded backbone infrastructure. | Entrepreneurship-driven model: any shop/entrepreneur can set up a PDO to sell Wi-Fi. |
User Access | Villagers access internet mainly via Common Service Centres (CSCs) and Gram Panchayats. | Citizens access internet directly via Wi-Fi hotspots in public spaces. |
Cost to Users | Affordable broadband, subsidized under USOF. | Free or low-cost Wi-Fi (depending on PDO operator). |
Vision Link | Part of Digital India – bridging the rural-urban digital divide. | Part of Digital India – ensuring universal, easy access to internet services in daily life. |
QUESTION 7
Consider the following situations:
Lift on an airfoil (wing): The wing deflects air downward; in response, the wing experiences an upward push (lift).
Swing/curve of a spinning ball (Magnus effect): The spinning ball deflects air to one side; the ball moves the other way.
Jet engine thrust: Hot exhaust gases are expelled backward; an equal forward thrust acts on the aircraft.
Which of the above are examples of Newton’s Third Law of Motion (for every action, there is an equal and opposite reaction)?
(a) 1 and 2 only
(b) 1 and 3 only
(c) 2 and 3 only
(d) 1, 2 and 3
Answer (d)
Explanation:
Newton’s Third Law: Action & Reaction
Newton’s Third Law: When object A exerts a force on object B, object B exerts an equal and opposite force on object A.
Lift on an airfoil is Correct: The wing pushes air downward (downwash). By Newton’s 3rd law, the air pushes the wing upward (lift).
Note: This complements pressure-based (Bernoulli) explanations; both views are consistent.
Spinning ball deflection is Correct (Magnus effect): The ball’s spin deflects the airflow sideways (action). The airflow exerts an opposite lateral force on the ball (reaction), making it curve.
Jet engine thrust is Correct: The engine expels mass (exhaust) backward at high speed (action). The engine/airframe receives an equal forward force (reaction) → thrust.
QUESTION 8
With reference to the Artemis Accords, consider the following statements:
They lay down a common set of principles to guide the civil exploration and peaceful use of outer space.
As of now, only seven nations along with NASA are signatories to these accords.
Which of the statements given above is/are true?
(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2
Answer (a)
Explanation:
Statement 1 is correct:
The Artemis Accords were launched in October 2020 by NASA, in coordination with the U.S. Department of State and partner nations.
They provide a common framework of principles for responsible behavior in space, focusing on transparency, interoperability, peaceful purposes, scientific data sharing, and sustainable use of space resources.
Aim: Enhance governance for civil space exploration — particularly missions to the Moon, Mars, comets, and asteroids.
Statement 2 is incorrect:
Initially, the Accords had eight founding signatories (NASA + 7 nations).
But as of 24 July 2025, the accords have 56 signatories (countries and agencies).
Hence, it is outdated to say “only 7 nations.”
Artemis Accords are non-binding agreements.
They complement (not replace) existing international frameworks like the Outer Space Treaty, 1967.
India signed the Artemis Accords in June 2023.
Artemis Accords vs Outer Space Treaty (OST, 1967)
Feature | Outer Space Treaty (1967) | Artemis Accords (2020) |
Nature | Legally binding international treaty adopted by the UN. | Non-binding set of principles coordinated by NASA & U.S. Department of State. |
Parties | 114 countries (as of 2025). | 56 signatories (as of July 2025, including India). |
Scope | Governs all activities in outer space (Moon, planets, satellites). | Focused on civil space exploration beyond Earth (Moon, Mars, comets, asteroids). |
Core Principles | - Outer space is the “province of all mankind.” - No sovereignty/national appropriation. - Ban on nuclear weapons in space. - States responsible for national activities. | - Transparency in missions. - Peaceful purposes only. - Interoperability & data sharing. - Preservation of heritage sites (e.g., Apollo landing sites). - Safe extraction & utilization of space resources. |
Enforcement | Monitored under UN framework; binding in international law. | Political/diplomatic instrument; relies on voluntary compliance. |
India’s Role | Ratified OST in 1982. | Signed Artemis Accords in June 2023. |
QUESTION 9
Which of the following factors are contributing to the increasing proliferation of jellyfish swarms in oceans?
1. Climate change
2. Plastic pollution
3. Overfishing
Select the correct answer using the codes given below:
(a) 1 and 2 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3
Answer (d)
Explanation:
Recently, one of France’s largest nuclear power plants was temporarily shut down due to a sudden influx of jellyfish blocking the cooling water intake system.
Such events have been reported globally since the 1990s — e.g., Gravelines (France, 1993), Japan, Sweden, Israel, and the U.S.
Factors contributing to jellyfish proliferation
Climate Change
Rising ocean temperatures due to global warming → more favorable conditions for jellyfish survival.
Warmer waters increase plankton (their main food supply), allowing jellyfish populations to expand.
Overfishing
Key predators of jellyfish (tuna, sea turtles) are being overfished.
This reduces natural population control of jellyfish.
Overfishing also removes other plankton-eating fish, leaving more food available for jellyfish.
Plastic Pollution
Pollution reduces oxygen levels in water (creating hypoxic zones).
Unlike many marine species, jellyfish are tolerant of low oxygen, giving them a competitive edge.
Plastic waste can also mimic prey (like jellyfish being mistaken for plastic bags by turtles), further disrupting predator-prey balance.
Impact of Jellyfish Blooms
Economic: Disrupt power plants, clog fishing nets, affect tourism.
Ecological: Alter food webs, dominate ecosystems.
Fisheries: Compete with fish for plankton, reducing fish stocks.
QUESTION 10
With reference to the stranding of whales along Indian coasts, consider the following statements:
Rising sea surface temperatures and ocean warming are causing ecological disruptions that contribute to whale strandings.
Whale strandings in India have increased nearly tenfold in the last decade.
Odisha and Andhra Pradesh have emerged as the primary hotspots for whale strandings.
How many of the statements given above are correct?
(a) Only one
(b) Only two
(c) All three
(d) None
Answer (b)
Explanation:
Statement 1 is Correct:
A study by ICAR-Central Marine Fisheries Research Institute (CMFRI) highlighted that rising sea surface temperatures (SSTs) and overall ocean warming disturb marine ecosystems.
These ecological disruptions, along with strong converging currents, increase the likelihood of weak or dead whales being dragged towards shores.
Statement 2 is Correct:
The study documented a tenfold rise in whale strandings along India’s southwest coast over the last decade.
Increased monitoring, citizen reporting, and social media attention have also added to higher reporting rates.
Statement 3 is Incorrect:
The real hotspots are along the southwest coast — mainly Kerala, Karnataka, and Goa — not Odisha and Andhra Pradesh.
These regions report the maximum strandings due to high vessel traffic, fishing activity, noise pollution, ship strikes, and shallow coastal shelves.
Other Key Drivers of Whale Strandings:
Noise pollution (from ships & sonar) → disorients whales.
Ship strikes → cause injuries/deaths.
Habitat degradation → reduces prey availability.
Environmental factors (e.g., ocean currents, storms) → drag carcasses or weak individuals ashore.
QUESTION 11
What are the major factors behind the Arctic’s rapid warming?
Albedo effect
Lack of convection in higher latitudes
Hot sea surface temperatures in the north-east Atlantic
Higher volcanic aerosol emissions
Upwelling of cold deep water
Select the correct answer using the codes given below:
(a) 1, 2 and 3
(b) 2, 3 and 5
(c) 1, 3 and 4
(d) All of the above
Answer (a)
Explanation:
The Arctic is warming nearly four times faster than the global average — a phenomenon called Arctic amplification.
Factors that drive rapid Arctic warming:
Albedo Effect is correct:
Albedo = reflectivity of a surface.
Sea ice reflects most incoming sunlight. But when ice melts, darker land/ocean surfaces are exposed, absorbing more heat.
This feedback loop accelerates Arctic warming.
Lack of Convection in High Latitudes is correct:
In the tropics, strong convection (upward movement of warm air) mixes heat vertically.
In the Arctic, weak convection traps heat near the surface, making warming more intense.
Hot Sea Surface Temperatures in NE Atlantic is correct:
A deep low-pressure system over Iceland (Feb 2022) pulled warm air from lower latitudes into the Arctic.
Warmer-than-usual sea surface temperatures (SSTs) in the north-east Atlantic intensified this inflow, raising Arctic air temperatures by 20°C above average.
Volcanic Aerosols is incorrect:
Aerosols from volcanic eruptions reflect sunlight → temporary cooling, not warming.
Upwelling of Cold Deep Water is incorrect:
Upwelling brings colder water to the surface, which counteracts warming locally, not accelerates it.
QUESTION 12
Consider the following statements regarding the neutral phase of the El Niño–Southern Oscillation (ENSO):
Statement 1: In the neutral phase, the eastern Pacific Ocean (near the northwestern coast of South America) is cooler than the western Pacific (near Indonesia and the Philippines).
Statement 2: This is because the prevailing wind systems move from west to east, sweeping colder surface waters towards Indonesia.
Which one of the following is correct?
(a) Both Statement 1 and Statement 2 are correct and Statement 2 is the correct explanation for Statement 1.
(b) Both Statement 1 and Statement 2 are correct and Statement 2 is not the correct explanation for Statement 1.
(c) Statement 1 is correct but Statement 2 is incorrect.
(d) Statement 1 is incorrect but Statement 2 is correct.
Answer (c)
Explanation:
ENSO (El Niño–Southern Oscillation): A climate phenomenon involving changes in sea surface temperatures (SSTs) and wind circulation across the tropical Pacific. It has three phases:
El Niño (warm phase)
La Niña (cool phase)
Neutral phase (normal conditions)
Statement 1 is Correct:
In the neutral phase, the eastern Pacific (near South America) is indeed cooler compared to the western Pacific (near Indonesia/Philippines).
Reason: continuous upwelling of cold water along the South American coast + stronger heating in western Pacific.
Statement 2 is Incorrect:
The winds responsible are trade winds, which blow east to west (not west to east).
These winds push the warm surface waters westward (towards Indonesia).
As warm water moves away from South America, cold deep water rises (upwelling) to replace it, keeping the eastern Pacific cooler.
El Niño phase: Trade winds weaken → warm water remains in east → eastern Pacific warms.
La Niña phase: Trade winds strengthen → more warm water pushed west → eastern Pacific becomes even cooler.
Impact on India:
El Niño → weaker monsoon, hotter summers
La Niña → stronger monsoon, cooler conditions
Feature | El Niño (Warm Phase) | La Niña (Cool Phase) | Neutral Phase |
Trade Winds | Weaken or reverse (east → west weakens) | Strengthen (east → west stronger than usual) | Blow normally from east → west |
Sea Surface Temperature (SST) | Eastern Pacific (South America) warms; Western Pacific cools slightly | Eastern Pacific cooler; Western Pacific warmer than usual | Eastern Pacific cooler; Western Pacific warmer (normal pattern) |
Upwelling (Cold Water Rising) | Suppressed near South America → less nutrient supply | Stronger near South America → more nutrients | Normal upwelling near South America |
Walker Circulation | Weakens or reverses | Intensifies | Normal strength |
Global Weather Impact | - Drought in India, Australia, SE Asia - Heavy rains in South America, USA | - Strong monsoon in India - Floods in Australia, SE Asia - Drier conditions in South America | Normal seasonal weather |
Impact on Indian Monsoon | Weak monsoon, less rainfall, hotter summers | Stronger monsoon, cooler conditions | Normal monsoon patterns |
QUESTION 13
Which of the following winds occur when high pressure builds over the Great Basin (between the Rocky Mountains and Sierra Nevada) and low pressure develops over coastal California?
(a) Chinook winds
(b) Bora
(c) Mistral
(d) Santa Ana winds
Answer (d)
Explanation:
Santa Ana winds are strong, dry downslope winds that blow from the inland deserts of the Great Basin towards the California coast when:
High pressure → over the Great Basin (interior desert plateau).
Low pressure → over coastal California and the Pacific.
This pressure gradient forces winds across mountains toward the coast.
Characteristics:
As the winds descend the mountains, they undergo adiabatic compression (air heats up as it is compressed).
Humidity drops sharply (sometimes < 10%).
They become hot, dry, and very strong.
Impact:
Dry out forests and vegetation.
Greatly increase the risk of wildfires in California.
Seasonality:
Most common between October and January, though they can occur in other months.
Considered a natural part of California’s climate system.
Regional Winds
Wind | Location | Type | Characteristics | Impacts |
Santa Ana | California, USA (from Great Basin to Pacific Coast) | Hot & dry downslope wind | - Forms when high pressure over Great Basin & low pressure over California coast - Very dry, humidity <10% - Strong, gusty | Fuels wildfires, dries vegetation, raises temp. |
Chinook | Eastern slopes of Rocky Mountains, USA & Canada | Warm downslope wind (“Snow eater”) | - Air descends Rockies, heats adiabatically - Sudden temp rise (10–20°C in hours) | Melts snow rapidly, beneficial for livestock, agriculture |
Mistral | Rhône Valley, Southern France into Mediterranean | Cold, dry, strong katabatic wind | - Blows from north/northwest toward Mediterranean - Funneled by Rhône Valley, speeds >100 km/h | Clears skies, but damaging to crops & vineyards |
Bora | Adriatic coast (esp. Croatia, NE Italy) | Cold, gusty katabatic wind | - Blows from north / northeast down mountains to Adriatic Sea - Very strong, violent gusts | Maritime hazards, sudden temp drop, damages structures |
QUESTION 14
In marine biology, the “wasting disease” observed in sea stars (starfish) is primarily associated with which phenomenon?
(a) Accumulation of plastic microfibres in the digestive tract causing starvation.(b) Formation of calcium deposits on the skin leading to shell hardening.(c) Detachment of limbs followed by disintegration of body tissue into organic residue.
(d) Development of abnormal spines due to mineral deficiency in seawater.
Answer (c)
Explanation:
Sea Star Wasting Disease (SSWD):
A severe marine epidemic affecting several species of sea stars (starfish).
Symptoms: lesions on the body, limb detachment, and rapid tissue decay, ultimately reducing the animal into organic residue (“pile of gunk”).
Geographic Spread:
Reported across the Pacific coast of North America — from Alaska’s cold waters to the warmer coasts of Mexico.
Most Affected Species:
Sunflower sea stars (Pycnopodia helianthoides) were hit hardest, with nearly 90% population loss.
Ecological Impact:
Sea stars are keystone predators in marine ecosystems.
Their decline led to exploding sea urchin populations (their prey).
Sea urchins in turn overgrazed kelp forests, which:
Provide habitat for marine biodiversity.
Play a role in carbon sequestration.
Thus, the disease disrupted the entire marine food web and coastal ecosystems.
QUESTION 15
With reference to the Himalayan region, consider the following statements:
The Himalayas are geologically young mountains with not fully consolidated rocks, which makes them more prone to landslides.
Seismic activity in the Himalayas can worsen the impact of extreme rainfall events.
Compared to the Aravali mountains, the Himalayas are less vulnerable to flash floods due to their higher altitude.
How many statements given above is/are correct?
(a) Only one
(b) Only two
(c) All three
(d) None
Answer (b)
Explanation:
Statement 1 is Correct:
The Himalayas are young fold mountains (still rising due to tectonic activity).
Their rocks are not fully consolidated, with fractured and weak geological structures.
This makes them highly prone to landslides and slope failures.
Statement 2 is Correct
The Himalayas are part of seismically active zones due to the ongoing collision between the Indian Plate and Eurasian Plate.
Earthquakes in this region can destabilize slopes and exacerbate the impact of heavy rainfall, triggering devastating landslides and flash floods.
Statement 3 is Incorrect
The Himalayas are actually more vulnerable to flash floods than the older, stable Aravali range.
Reasons: steep slopes, high relief, fragile geology, heavy rainfall, and glacial meltwater.
The Aravalis, being ancient and eroded, face less intense flash flood risk compared to the Himalayas.
Other Contributing Factors:
Large-scale construction (roads, dams, tunnels).
Tourism and vehicular pressure.
Poor disposal of debris/boulders near riverbanks.
QUESTION 16
The Green Climate Fund (GCF), considered the world’s largest dedicated climate finance fund, was established within the framework of:
(a) Stockholm Convention
(b) Convention on Biological Diversity
(c) Ramsar Convention
(d) UNFCCC
Answer (d)
Explanation:
The Green Climate Fund (GCF) is a financial mechanism created under the United Nations Framework Convention on Climate Change (UNFCCC).
It was formally established at the 16th Conference of Parties (COP 16), 2010 in Cancun, Mexico, and became operational in 2014.
Objective:
Provide financial support to developing countries for:
Mitigation (reducing greenhouse gas emissions).
Adaptation (building resilience against climate impacts).
Scale:
It is the world’s largest dedicated climate finance fund.
Developed nations have pledged US$100 billion annually by 2020 (commitment extended to 2025) for climate finance, partly through the GCF.
Governance:
The GCF is headquartered in Songdo, South Korea.
Managed by a Board of 24 members (equal representation of developed and developing countries).
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