UPSC Current Affairs Quiz : 6 April 2026

Solution: B

• Coal gasification is a sophisticated process designed to utilize coal more cleanly. Unlike traditional coal-fired power plants that rely on combustion (burning coal in the presence of abundant oxygen), gasification involves partial oxidation. This means coal is reacted with steam and controlled amounts of oxygen under high pressure and temperature to break down its molecular structure rather than burning it. Therefore, statement 1 is incorrect as it mentions complete combustion.
• The primary product of this reaction is syngas (synthesis gas), which is a pressurized mixture consisting mainly of carbon monoxide (CO) and hydrogen (H2), with smaller amounts of methane. This makes statement 3 correct.
• One of the major environmental advantages of gasification is pre-combustion cleaning. Before the syngas is used in turbines or as a chemical feedstock, it is processed to remove impurities like particulate matter, sulfur, and mercury. This is significantly more efficient than post-combustion scrubbing used in traditional plants.
• Consequently, statement 2 is correct. The versatility of syngas allows it to be used for electricity, fertilizers like urea, and even liquid fuels, supporting India’s energy security goals.

Solution: B

• Earthquake Lights (EQL) are rare, luminous events documented before or during seismic activity. They result from lithospheric-atmospheric coupling, where intense tectonic stress in the Earth’s crust—specifically in igneous rocks—activates charge carriers known as p-holes. These charges travel rapidly through fault systems to the surface. Upon reaching the interface with the atmosphere, they ionize the air, creating a luminous plasma-like discharge, confirming statements 1 and 3.
• Interestingly, research indicates that these lights are not common at all types of plate boundaries. Approximately 97% of documented cases occur at or near rift zones or sub-vertical fault systems where tectonic plates are pulling apart (extensional environments), rather than subduction zones. This makes statement 2 incorrect.
• EQL can manifest in various forms, including floating spheres (ball lightning) or steady glows. Because they often appear as pre-seismic events, they hold potential as a visual early-warning signal. This phenomenon bridges the gap between folklore and geophysics, allowing scientists to study the electrical properties of the crust under extreme stress.

Solution: A

• INS Aridhaman is the third indigenous submarine of the Arihant-class. As an SSBN (Ship Submersible Ballistic Nuclear), it is specifically designed to carry nuclear-tipped ballistic missiles. India’s nuclear doctrine is based on No First Use (NFU), which necessitates a “credible minimum deterrence” and a guaranteed second-strike capability. This means that even if an adversary destroys India’s land-based and air-based nuclear assets in a first strike, India must be able to retaliate from the sea.
• The reason INS Aridhaman (and SSBNs in general) provides this capability is its nuclear propulsion. Powered by an 83 MW pressurized light-water reactor, the submarine does not need to surface to recharge batteries (unlike diesel-electric submarines). It can remain submerged, silent, and virtually untraceable for months, limited only by crew supplies. This stealth and endurance ensure that the vessel remains a “survivable” nuclear platform.
• Therefore, Statement-II directly explains why Statement-I is true—the technical nature of being a nuclear-powered ballistic missile submarine is exactly what grants the strategic second-strike advantage.

Solution: D

• The Hindu Kush is a massive 800-kilometre-long mountain range that forms a vital part of the Great Alpine-Himalayan system. It is geologically complex and spans across eight nations: Afghanistan, Pakistan, India (specifically the Union Territory of Ladakh), Tajikistan, Kyrgyzstan, Uzbekistan, China, and Iran. In Iran, the range transitions into lower hills, while in the east, it merges with the Pamir Knot and the Karakoram Range.
• The range is a result of the ongoing tectonic collision between the Indian and Eurasian plates, making it one of the most seismically active zones globally. It serves as a major watershed, separating the Amu Darya valley to the north from the Indus River basin to the south.
• Historically, the Hindu Kush has been a formidable barrier and a crossroads of civilizations, featuring critical transit points like the Khyber Pass and the Salang Pass. Its glaciers are essential for the water security of millions in the region. Since it touches all the nations listed in the options, the correct code includes all five.

Solution: A

• The No-Cloning Theorem is the fundamental security guard of Quantum Cryptography. In a classical system, a hacker can intercept a data packet, copy it, and send the original along its way without the sender or receiver ever knowing. In the quantum world, the theorem states that you cannot make an exact copy of an unknown quantum state. Any physical process that tries to “measure” or “copy” a qubit forces it out of its superposition or otherwise disturbs the state.
• Consequently, if an eavesdropper tries to intercept a quantum key, the unavoidable disturbance they cause will result in errors that the legitimate users can detect. This makes the communication “tamper-evident.”
• Option (b) is incorrect as cloning is prohibited.
• Option (c) is incorrect because the theorem actually makes it difficult to amplify signals (leading to the need for quantum repeaters).
• Option (d) is incorrect as qubits cannot be perfectly mapped to classical bits without losing quantum properties. This theorem creates a clear quantum-classical divide, where quantum information is fragile and unique, whereas classical information is robust and replicable.

Solution: D

• Azerbaijan, often called the “Land of Fire,” is a transcontinental nation in the Caucasus region.
• Pair I is correctly matched; the capital, Baku, is situated on the Absheron Peninsula, which juts into the Caspian Sea. This area is historically significant for its oil and gas seeps.
• Pair II is also correct. Azerbaijan is home to nearly half of the world’s mud volcanoes. Unlike igneous volcanoes, these erupt with cold mud and methane gas, reflecting the country’s unique geological and hydrocarbon profile.
• Pair III is correctly matched as well. Nakhchivan is an autonomous exclave of Azerbaijan. It is physically separated from the main body of the country by Armenia. It shares a long border with Iran to the south and a very short, strategic border with Turkey to the northwest.
• Azerbaijan’s geography is dominated by the Greater Caucasus to the north and the central Kura-Aras lowland. It serves as a critical link in the International North-South Transport Corridor (INSTC), connecting India to Russia.

Solution: B

• The Hindu Kush is a critical component of the Great Alpine-Himalayan system, representing its western extension. It was formed by the collision of the Indian and Eurasian plates, which continues to cause deep-seated earthquakes in the region, such as the recent event near Jurm. Therefore, statement 1 is correct.
• It also acts as a massive hydrographic divide. The northern slopes feed the Amu Darya (the ancient Oxus River), which flows toward the Aral Sea basin, while the southern slopes feed tributaries of the Indus River. Thus, statement 2 is correct.
• Statement 3 is incorrect. While much of the range lies within Afghanistan, its highest point is Tirich Mir, which stands at 7,708 metres. Tirich Mir is located in the Chitral District of Pakistan, not Afghanistan. The range is characterized by its rugged, jagged peaks and narrow valleys, which have historically limited movement between Central and South Asia.
• The Salang Pass tunnel, located in the Hindu Kush, is one of the few year-round links between northern and southern Afghanistan, highlighting the range’s strategic and geographical importance.

Solution: A

• Statement 1 is correct. Azerbaijan is technically a landlocked nation. Although it has a long coastline along the Caspian Sea, the Caspian is an endorheic basin (an inland sea) with no natural, direct opening to the global oceans. Access to the high seas requires transit through Russia’s canal systems or other nations.
• Statement 2 is also correct. The Kura-Aras Lowland is the central heartland of the country, a large plain and valley system created by the confluence of the Kura and Aras rivers, which is vital for the country’s agriculture.
• Statement 3 is incorrect. Azerbaijan’s longest border is with Armenia (approx. 1,000 km), largely due to the complex and disputed frontier in the Lesser Caucasus region. While it shares a significant border with Iran to the south, it is not its longest. The country is geographically diverse, featuring the high peaks of the Greater Caucasus to the north and the subtropical Lenkoran Lowland in the south. Its location makes it a critical energy corridor for Europe, exporting vast amounts of oil and gas from its Caspian offshore fields.

Solution: C

• The safety of Piped Natural Gas (PNG) stems largely from its chemical composition, which is primarily methane. Methane has a lower density than air, meaning PNG is lighter than air. In the event of a leak, it disperses rapidly into the atmosphere rather than accumulating at floor level. This significantly reduces the risk of accidental fire or explosions, which is a major concern with LPG (butane and propane), as LPG is heavier than air and tends to settle in low-lying areas.
• Statement (b) is incorrect because PNG is delivered via pipelines, eliminating the need for storage tanks at home. Statement (d) is incorrect as PE pipes are typically used for the secondary network (neighborhoods), while the primary trunk lines use steel.

Solution: C

• Statement 1 is correct; E20 petrol consists of 20% ethanol derived from sugarcane, maize, and grains.
• Statement 3 is correct; while ethanol allows for cleaner combustion, it has a lower energy density than pure petrol, which can result in a slight reduction in fuel efficiency, especially in older engines not optimized for high-ethanol blends.
• However, Statement 2 is incorrect. Ethanol actually has a higher octane rating (approx. 95 RON) compared to regular petrol (91-92 RON). This high octane rating allows for smoother combustion and prevents “knocking,” which is beneficial for engine performance. The mandate for nationwide E20 use aims at energy self-reliance and reducing crude oil import costs.