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UPSC Prelims S.E.E. Snapshot: GPS interference, RBI’s Monetary Policy, Heatwaves

From ships ‘jumping’ locations due to GPS interference to how the RBI controls inflation—and what heatwave criteria are—here are 3 key concepts simplified for UPSC Prelims 2026.

UPSC Prelims S.E.E. Snapshot: GPS interference, Monetary Policy, Heatwaves— quick lookHere are three important topics from Science, Economy, and Environment decoded through the Prelims lens—focusing on concepts and clarity. (Image: AI generated)

Short on time before UPSC Prelims and struggling with tricky concepts? The exam increasingly tests your conceptual clarity and ability to apply core ideas, especially in the most dynamic subjects: Science, Economy, and Environment (SEE).

UPSC Essentials’ new initiative, UPSC Prelims ‘SEE’ Snapshot, brings you, every Wednesday, a quick, exam-focused revision of key concepts. In each article, we pick three important current themes from Science, Economy, and Environment and decode them strictly through the Prelims lens—focusing on concepts and clarity.

If you missed the previous UPSC Prelims S.E.E. Snapshot: VitalID, Non-deliverable derivative, Galactic cosmic rays— quick look from the Indian Express, read it here.

SCIENCE

GPS interference  

Why it matters

In the US-Iran war, in addition to physical warfare, both sides have seen their navigation systems go haywire, erroneously indicating that ships were located at airports, on land or at nuclear power plants. This has been made possible through electronic interference, such as GPS spoofing or jamming. In this context, it is important to understand what GPS interference is. 

Core Concept: 

— Both ships and aircraft depend on global navigation satellite systems (GNSS) for position, navigation, and timing (PNT) information. Of these, the American Global Positioning System (GPS) is the most popular GNSS, with the terms often used interchangeably. But there are other GNSSs as well, like Europe’s Galileo, Russia’s GLONASS, China’s BeiDou and India’s NavIC 

— GPS interference refers to spoofing or jamming, two types of deliberate cyber-attacks on Global Positioning System (GPS) signals, which disrupt or deceive vehicles’ navigation systems. While both are often used synonymously with each other, spoofing and jamming refer to slightly different kinds of interference. 

GPS jamming involves a device (jammer) emitting strong radio signals on GPS frequencies in order to overpower weaker signals. This disrupts the functioning of GPS systems by rendering receivers unable to determine location or time. 

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— GPS spoofing involves a device transmitting signals on the same frequencies used by GPS satellites, overwhelming or blocking the GPS receivers from acquiring or maintaining the right satellite signals. Unlike jamming, which disrupts signals entirely, spoofing deceives the receiver into trusting false data. 

UPSC Prelims S.E.E. Snapshot: GPS interference, Monetary Policy, Heatwave— quick look (Image: Created by Google NotebookLM)

Of the two, spoofing is the more serious offence, disrupting signals and forcing pilots, for instance, to incorrectly account for factors such as altitude or terrain. Spoofing may tell an aircraft it is in a location it isn’t supposed to be in, and create confusion in the cockpit. 

📍UPSC Twist Points– GPS interference vs Trojan horse and Phishing

  Trojan horse is a destructive program that looks like a genuine application. Unlike viruses, Trojan horses do not replicate themselves but they can be just as destructive. Trojans open a backdoor entry to your computer which gives malicious users/programs access to your system, allowing confidential and personal information to be theft. 

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— Phishing: It is a common type of cyber-attack that targets individuals through email, text messages, phone calls, and other forms of communication. A phishing attack aims to trick the recipient into falling for the attacker’s desired action, such as revealing financial information, system login credentials, or other sensitive information. Fundamentally, these threats exploit human psychology rather than technical vulnerabilities. 

ECONOMY

Monetary Policy

Why it matters 

The Monetary Policy Committee (MPC) on April 8 kept the policy repo rate unchanged at 5.25%. However, the central bank projected that India’s GDP growth will decline to 6.9% in 2026-27 from 7.6% in 2025-26. On the other hand, headline retail inflation is set to average 4.6% in the current fiscal. Given that UPSC has previously asked questions on monetary policy, it becomes important to take a closer look and understand it. 

Core Concept: 

Monetary policy refers to the use of monetary instruments under the control of the central bank to influence variables, such as interest rates, money supply and the availability of credit, with a view to achieving the objectives of the policy.  The monetary policy is used by the RBI to maintain price stability while keeping in mind the objective of growth. 

— Notably, in May 2016, the RBI Act was amended to provide a legislative mandate to the central bank to operate the country’s monetary policy framework. The framework, according to the RBI website, “aims at setting the policy (repo) rate based on an assessment of the current and evolving macroeconomic situation and modulation of liquidity conditions to anchor money market rates at or around the repo rate.”

UPSC Prelims S.E.E. Snapshot: GPS interference, Monetary Policy, Heatwave— quick look

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— Various direct and indirect instruments are used by the RBI for implementing monetary policy, including Repo Rate, Reverse Repo Rate, Marginal Standing Facility (MSF), Liquidity Adjustment Facility (LAF), Bank Rate, Cash Reserve Ratio (CRR), Open Market Operations (OMOs) and Market Stabilisation Scheme (MSS).  

 

RBI & Monetary Policy — UPSC Explainer

ECONOMICS — UPSC PREP
A four-part explainer on India's monetary policy framework — what it is, the tools RBI uses, who sets the rates, and how decisions are made.
DEFINITION
RBI's tool to steer the economy
Monetary policy is the use of instruments — interest rates, money supply, credit availability — by the RBI to achieve price stability and growth. The RBI Act was amended in May 2016 to give the central bank a formal legislative mandate to operate this framework.
2016
Year RBI got legislative mandate via RBI Act amendment
4%
CPI inflation target set by govt (±2% band)
TWIN OBJECTIVES
Price stability + Growth
The framework aims to set the policy (repo) rate based on macroeconomic assessment and modulate liquidity to anchor money market rates at or around the repo rate. The Central Government sets the CPI inflation target every five years in consultation with the RBI.
Repo Rate
Policy rate at which RBI provides overnight liquidity to banks against govt securities under LAF. Set by the MPC.
Reverse Repo Rate
Rate at which RBI absorbs overnight liquidity from banks against eligible govt securities under LAF.
MSF Rate
Marginal Standing Facility — emergency overnight borrowing from RBI when interbank liquidity dries up. Placed 25 bps above repo rate.
SDF Rate
Standing Deposit Facility — RBI accepts uncollateralised deposits from LAF participants. Introduced in 2022 as LAF corridor floor, replacing FRRR.
CRR & SLR
Cash Reserve Ratio: % of NDTL kept as liquid cash with RBI. Statutory Liquidity Ratio: % held in cash, gold, or govt securities.
OMOs & MSS
Open Market Operations inject or absorb durable liquidity via govt securities. Market Stabilisation Scheme manages enduring surplus from capital inflows.
CONSTITUTION
6-member body under Section 45ZB
The Monetary Policy Committee was constituted under the amended RBI Act, 1934. It determines the policy rate to achieve the inflation target. The first MPC was constituted on September 29, 2016.
6
Total MPC members
3
Govt-appointed external members
3
RBI internal members
RBI Governor
Ex officio Chairperson of the MPC. Currently Sanjay Malhotra.
Deputy Governor (Monetary Policy)
The Deputy Governor in charge of monetary policy.
RBI Officer (Central Board nominee)
An officer of the Bank nominated by the RBI Central Board.
Minimum 4 meetings per year
The MPC is required to meet at least four times annually to review and set the policy rate.
Quorum of 4 members
A minimum of 4 members must be present for any MPC meeting to be valid and decisions to be binding.
One vote per member
Each of the 6 MPC members holds one vote. Decisions are by majority.
Governor's casting vote
In case of a tie (equality of votes), the RBI Governor exercises a second or casting vote to break the deadlock.
Decision is binding on RBI
Under Section 45ZB, the MPC's rate decision is legally binding on the Reserve Bank of India.
TAGS
Monetary Policy RBI Repo Rate MPC UPSC Economics Inflation
Sources: Reserve Bank of India (rbi.org.in) · RBI Act, 1934 (amended 2016) · Section 45ZA, 45ZB, 45ZC
Express InfoGenIE
 

📍UPSC Twist Points– Monetary Policy vs Fiscal Policy

— Both monetary policy and fiscal policy serve as critical tools for managing the economy of our country. One key distinction between monetary and fiscal policy lies in their implementation authorities and tools. Monetary policy is formulated and implemented by the RBI, which primarily focuses on regulating the money supply, interest rates, and inflation levels. 

— On the other hand, the government makes decisions pertaining to fiscal policy, and the Ministry of Finance plays a central role in formulating budgets, tax policies, and expenditure plans. The government employs fiscal policy to manage aggregate demand, promote growth, and address socioeconomic challenges.

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— Additionally, monetary policy tends to affect borrowing costs and financial markets more immediately, which affects investment and consumption patterns. Fiscal policy measures, on the other hand, such as tax reforms or infrastructure spending, may have longer-term and more extensive effects on economic development and growth.

 

ENVIRONMENT

Heatwaves

Why it matters 

April this year is once again turning unusually hot in Punjab and Haryana, with the India Meteorological Department (IMD) issuing repeated heatwave alerts for several districts over the past few days. Traditionally, heatwave conditions in the region were associated with May and June, but over the past decade, April sometimes itself has begun to witness such spells — particularly towards the latter half of the month. 

Core Concept: 

— According to the Indian Meteorological Department (IMD), a heatwave is a period of abnormally high temperatures, more than the normal maximum temperature that occurs during the summer season in the North-Western parts of India. Heatwaves typically occur between March and June, and in some rare cases even extend till July. 

— The extreme temperatures and resultant atmospheric conditions adversely affect people living in these regions as they cause physiological stress, sometimes resulting in death.

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—  A heatwave is declared when the maximum temperature of a station reaches at least 40°C or more for plains, 37°C or more for coastal stations, and at least 30°C or more for hilly regions. Based on departure from normal temperatures, the following criteria are used to declare a heatwave:

(i) Heatwave: Departure from normal is 4.5°C to 6.4°C.

(ii) Severe Heatwave: Departure from normal is 6.4°C.

— Based on the actual maximum temperature in plains, the following criteria is considered:

(i) Heatwave: When the actual maximum temperature ≥ 45°C

(ii) Severe Heatwave: When actual maximum temperature ≥47°C

— If the above criteria met at least in 2 stations in a Meteorological sub-division for at least two consecutive days and it was declared on the second day.

IMD Criteria
How India Declares a Heatwave: Thresholds by Terrain & Severity
Minimum Temperature to Declare a Heatwave
🏙 Plains
40°C
Maximum temperature threshold
🌊 Coastal
37°C
Lower due to humidity factors
⛰ Hilly Regions
30°C
Mountains heat up faster
Method 1 — Departure from Normal Temperature
🌡 Heatwave
4.5°C – 6.4°C
above normal max temp
🔥 Severe Heatwave
>6.4°C
above normal max temp
Method 2 — Actual Max Temperature (Plains Only)
🌡 Heatwave
≥ 45°C
actual maximum temperature
🔥 Severe Heatwave
≥ 47°C
actual maximum temperature
📌 Declared only when criteria are met at 2+ stations in a meteorological sub-division for 2 consecutive days — announced on the second day.
⚠️ The Wet Bulb Factor: Heatwaves turn especially fatal when high temperatures coincide with high humidity — a condition known as wet bulb.
Indian Express InfoGenIE

— Heatwaves are especially fatal when high temperatures coincide with high humidity, a condition known as a wet bulb.  

📍UPSC Twist Points– Heatwave vs Heat dome

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A heat dome occurs when an area of high-pressure stays over a region for days and weeks. It traps warm air, just like a lid on a pot, for an extended period. The longer that air remains trapped, the more the sun works to heat the air, producing warmer conditions with every passing day. 

— Heat domes, if they last for a long period, may cause deadly heatwaves. 

Prelims Practice MCQ

Let’s see how much can you recall

Consider the following statements:

1. GPS spoofing disrupts navigation systems by completely blocking signals, making receivers unable to determine location or time.

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2. Monetary policy in India is implemented by the central government.

3. A heatwave is declared when the maximum temperature of a station reaches at least 40°C or more for plains

Which of the statements given above is/are correct?

(a) 2 and 3 only

(b) 1 and 2 only

(c) 1 and 3 only

(d) 3 only

Answer
(d)

UPSC Prelims ‘SEE’ Snapshot: Talking cars, GDP rebasing and Nor’westers — quick look 

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Roshni Yadav is a Deputy Copy Editor with The Indian Express. She is an alumna of the University of Delhi and Jawaharlal Nehru University, where she pursued her graduation and post-graduation in Political Science. She has over five years of work experience in ed-tech and media. At The Indian Express, she writes for the UPSC section. Her interests lie in national and international affairs, governance, the economy, and social issues. You can contact her via email: roshni.yadav@indianexpress.com. ... Read More

 

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