Daily Current Affairs

June 26, 2025

Current Affairs

Cooking oils can help recover Silver from e-waste

Context: Scientists have developed a groundbreaking technique to recover silver from electronic waste using organic fatty acids found in cooking oils. This offers a safer, cost-effective, and environmentally friendly alternative to traditional chemical recycling processes.

Relevance of the Topic: Prelims: Key facts about Silver; Applications of Silver in the clean energy transition.

Cooking oils can help recover Silver from e-waste

  • Traditional silver recovery methods involve toxic chemicals like cyanide and strong acids, which are highly toxic, corrosive and harmful to the environment.
  • The newly discovered method uses natural fatty acids (like those in sunflower or olive oil) to recover silver from electronic waste without releasing harmful toxins. 
  • To dissolve silver, the most commonly used unsaturated fatty acids- oleic, linoleic and linolenic- were combined with an aqueous hydrogen peroxide (30%) solution as a green oxidant under mild conditions. This combination effectively dissolved silver into the fatty acids. This dissolved silver can be later recovered.  
  • Utility: The method can be applicable to urban mining, to retrieve silver from waste electrical and electronic wastes (WEEE) from discarded computer motherboard pieces. 

Need for better recycling methods: 

  • Silver is used to capture sunlight through rooftop solar panels across India, generating about 108 GW of clean and green electricity yearly across the nation (about 10% of what is generated from coal). Silver is also used in Mobile phones and laptops. 
  • It is estimated that about 7,275 metric tonnes of silver are used across the world for these purposes, but barely 15% is recovered (When a phone or a computer is damaged or discarded, the silver content is lost).
  • With the global shift toward renewable energy and electric vehicles, the demand for silver is expected to rise by 170% by 2020. This calls for better recycling methods.

The research team concludes that fatty acids may become the next generation of solvents for treating precious multi-metal waste substrates. 

QS World University Rankings 2026

Context: India has marked its strongest performance in the QS World University Rankings 2026 with 54 institutions featured in the list. 

Relevance of the Topic: Prelims: Key Highlights- QS World University Rankings 2026. 

QS World University Rankings 2026

Global Highlights: 

  • QS World University Rankings 2026 were topped by: Massachusetts Institute of Technology (MIT), followed by Imperial College London, Stanford University, University of Oxford, and Harvard University. 

India-specific Highlights: 

  • The number of Indian universities in the rankings has grown from 11 in 2015 to 54 in 2026. Six Indian institutions feature in the global top 250.
  • Indian Institute of Technology (IIT) Delhi has emerged as India’s highest-ranked university, with 123rd position, followed by IIT Bombay and IIT Madras. 
  • India has become the fourth most represented country in the global rankings, behind the US, UK, and China. It positions India as the fastest-growing higher education system among G20 nations. 

Challenges: 

India continues to face challenges in aspects critical to global competitiveness, such as international student diversity and faculty resources.

  • International Students Ratio: 78% of Indian universities have witnessed a decline in this metric, and no Indian institution ranks within the top 500 globally for attracting international students. This impacts campus diversity and global exposure for students.
  • Faculty-Student Ratio presents structural challenges, highlighting a broader need for faculty expansion and better resource allocation across institutions. 

QS World University Rankings: 

  • The QS World University Rankings are among the most trusted and wide-reaching assessments of higher education worldwide. 
  • The 2026 edition is based on data from over 16 million academic papers and insights from more than 151,000 academics and 100,000 employers. 
  • The rankings consider a broad mix of factors such as: Academic Reputation, Citations per Faculty, Faculty Student Ratio, Research strength, Employment Outcomes, Faculty Student Ratio, International Student Diversity, International Student Ratio etc. 

This upward trajectory in QS University rankings reflect growing focus on improving the quality and international visibility of Indian higher education institutions, however, there is room for improvement.

What is Synthetic Aperture Radar?

Context: NASA and ISRO are set to launch the NISAR (NASA-ISRO SAR) satellite, a $1.5 billion Earth-observing mission in July 2025. NISAR has arrived at ISRO’s spaceport in Sriharikota, Andhra Pradesh. 

Relevance of the Topic: Prelims: Key facts about Synthetic Aperture Radar; Advantages & Applications of SAR

Synthetic Aperture Radar: 

  • Synthetic aperture radar (SAR) is a form of active remote sensing that uses microwave radar signals to create high-resolution images of Earth. 

How does SAR work?

  • SAR systems send out microwave pulses towards Earth. These signals bounce off from surfaces like ground, ocean, ice, vegetation, buildings etc. 
  • These echoes (reflected signal) are collected by the antenna carried on a moving platform like a satellite. Since the satellite is moving, each echo is recorded at a slightly different position. 
  • Via complex signal processing those echoes are stitched together into detailed images. Usually, the longer a physical antenna, the better is the resolution. However, a large antenna is hard to build and maintain. Hence, SAR mimics the effect of having a single giant antenna (hundreds of metres long). 
image 42

Advantages of SAR: 

  • Since microwaves penetrate clouds, smoke, dense vegetation, and even light rainfall, SAR can collect data 24/7.
  • If a SAR unit is mounted on an orbiting satellite, it can map swaths of land hundreds of kilometres wide in a single overpass. 
  • Different materials like soil, vegetation, water, and metals reflect microwaves differently, allowing SAR to detect changes invisible to optical sensors.

Applications of SAR: 

SAR can observe natural processes and changes in earth’s complex ecosystems. 

  • Study Earth’s dynamic land and ice surfaces in greater detail and observe subtle changes in Earth’s surfaces. E.g., Track flow rates of glaciers and ice sheets, landslide-prone areas and changes in the coastline etc.
  • Spot warning signs of natural disasters, such as earthquakes, tsunamis, volcanoes and landslides.
  • Measure groundwater levels, agricultural mapping, vegetation biomass, natural resource mapping and monitor Earth’s forest and agricultural regions to improve understanding of carbon exchange. 

NISAR will scan nearly all of Earth’s land and ice surfaces twice every 12 days, providing an unprecedented amount of information about our planet’s environment.

Also Read: NASA-ISRO Synthetic Aperture Radar

Flash Flood in Subarnarekha River

Context: The Subarnarekha River has flooded large parts of Balasore district in Odisha, affecting over 50,000 people and inundating dozens of villages.

Relevance of the Topic: Prelims: Key facts about Subarnarekha River; Flash Flood. 

Subarnarekha River

  • Subarnarekha (literally means Streak of Gold) is a rain-fed river that originates near Ranchi, the capital of Jharkhand on the Chhotanagpur plateau.
  • The river flows through Jharkhand, West Bengal, Odisha and drains into the Bay of Bengal. The total length of the river is 395 kilometres. 
  • Kanchi and Karkari rivers are its chief tributaries.
  • Subarnarekha passes through areas with extensive mining of copper and uranium ores. As a result of unplanned mining activities, the river is polluted. It has been the lifeline of tribal communities inhabiting the Chhotanagpur region, and water pollution affects their livelihood. 
image 41

Flood and Flash Flood:

  • Flood: An overflow of water onto normally dry land. The inundation of a normally dry area caused by rising water in an existing waterway, such as a river, stream, or drainage ditch. Ponding of water at or near the point where the rain fell. Flooding is a longer term event, it may last days or weeks.
  •  Flash flood: A flood caused by heavy or excessive rainfall in a short period of time, generally less than 6 hours. It can also occur even if no rain has fallen, for instance after a levee or dam has failed, or after a sudden release of water by a debris or ice jam. The intensity of the rainfall, the location and distribution of the rainfall, the land use and topography, vegetation types and growth/density, soil type, and soil water-content all determine the intensity and impact caused by flash flood. 

Also Read: Small peninsular rivers flowing towards East

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