The 2018 Codex
Questions 81 to 90 (Set A)
Which of the following is/are the possible consequence/s of heavy sand mining in riverbeds?
1. Decreased salinity in the river
2. Pollution of groundwater
3. Lowering of the water-table
Select the correct answer using the code given below:
The Secret Whisper
Official Key: (b) 2 and 3 only
Statement 1 is False: Heavy sand mining deepens the riverbed, often pushing it below sea level near coastal areas. This causes highly saline seawater to rush upstream into the river (saltwater intrusion), significantly increasing the salinity of the river, not decreasing it.
Statements 2 & 3 are True: Sand acts as a natural sponge and filter for rivers. By stripping away this sand bed, the river loses its ability to hold and percolate water downward, severely lowering the water table. Additionally, without the sand acting as a biological filter, heavy metals and pollutants easily seep down, leading to the pollution of groundwater.
Route: [REALM 118: Water Resources Degradation] & [REALM 127: Mining Governance & Law]The Hollowed Bed
The Salt Crust
With reference to agricultural soils, consider the following statements:
1. A high content of organic matter in soil drastically reduces its water holding capacity.
2. Soil does not play any role in the sulphur cycle.
3. Irrigation over a period of time can contribute to the salinization of some agricultural lands.
Which of the statements given above is/are correct?
The Secret Whisper
Official Key: (b) 3 only
Statement 1 is False: Organic matter (humus) acts exactly like a sponge. It significantly increases the soil's water-holding capacity, not reduces it.
Statement 2 is False: The sulphur cycle is mostly sedimentary. Soil acts as a massive reservoir for sulphur (in the form of sulfates), and soil microorganisms play an essential role in breaking it down for plants to absorb.
Statement 3 is True: Over-irrigation, especially in arid or semi-arid regions without proper drainage, raises the groundwater table. Through capillary action, water rises to the surface and evaporates, leaving behind a toxic crust of salts—a process called salinization.
Route: [REALM 38: Soil Texture & Properties] & [REALM 19: Salinity, Sodicity & Waterlogging]The Partnership for Action on Green Economy (PAGE), a UN mechanism to assist countries transition towards greener and more inclusive economies, emerged at
The Secret Whisper
Official Key: (b) The United Nations Conference on Sustainable Development 2012, Rio de Janeiro
The Partnership for Action on Green Economy (PAGE) was formed in direct response to the call at the Rio+20 United Nations Conference on Sustainable Development in 2012. The summit produced the landmark outcome document "The Future We Want," and PAGE was established by five UN agencies (UNEP, ILO, UNDP, UNIDO, and UNITAR) to put that document into action by helping nations shift to inclusive, green economies.
Route: [REALM 182: International Sustainable Development]The Green Catalyst
The Genesis Nozzle
"3D printing" has applications in which of the following?
Select the correct answer using the code given below:
The Secret Whisper
Official Key: (d) 1, 2, 3, 4 and 5
UPSC frequently tests emerging tech like 3D printing (Additive Manufacturing). Because it is a foundational, general-purpose technology, its applications are nearly limitless. Yes, 3D printers can print intricate chocolate and candy shapes (confectionery). They print titanium bone implants for reconstructive surgery and bio-printed bionic ears. They print lightweight automotive parts. And they are increasingly used to print highly complex, multi-material micro-architectures used in quantum and advanced data processing technologies.
Route: [REALM 201: Fourth Industrial Revolution] & [REALM 243: Digital Manufacturing]Consider the following statements:
1. The Barren Island volcano is an active volcano located in the Indian territory.
2. Barren Island lies about 140 km east of Great Nicobar.
3. The last time the Barren Island volcano erupted was in 1991 and it has remained inactive since then.
Which of the statements given above is/are correct?
The Secret Whisper
Official Key: (a) 1 only
Statement 1 is True: Barren Island is the only confirmed active volcano in India (and the entire sequence of islands from Sumatra to Myanmar).
Statement 2 is False: Barren Island is located about 138 km northeast of Port Blair (Middle Andaman), not Great Nicobar. Great Nicobar is way down south near Sumatra.
Statement 3 is False: While it did have a major eruption in 1991, it has absolutely not remained inactive. It has erupted multiple times since then, notably in 2005, 2017, and 2018 (which is why it was in the news for this paper).
Route: [REALM 31: Volcanoes] & [REALM 12: Coastal Plains & Islands]The Solitary Peak
The Invader's Roots
Why is a plant called Prosopis juliflora often mentioned in news?
The Secret Whisper
Official Key: (b) It tends to reduce the biodiversity in the area in which it grows.
Prosopis juliflora (often called Vilayati kikar/babul) is an extremely aggressive Invasive Alien Species. It was introduced to India by the British in the late 19th century to green the dry tracts of Delhi and Rajasthan. It has incredibly deep tap roots that aggressively suck up groundwater, drying out the soil and completely choking out native flora. Governments across states (like Tamil Nadu and Delhi) frequently mandate mass drives to uproot it to save local biodiversity.
Route: [REALM 69: Invasive Alien Species]Consider the following statements:
1. Most of the world's coral reefs are in tropical waters.
2. More than one-third of the world's coral reefs are located in the territories of Australia, Indonesia and Philippines.
3. Coral reefs host far more number of animal phyla than those hosted by tropical rainforests.
Which of the statements given above is/are correct?
The Secret Whisper
Official Key: (d) 1, 2 and 3
Statement 1 is True: Reef-building corals require warm water (typically 20°C to 28°C) and are mostly restricted to shallow, clear tropical waters between 30°N and 30°S latitude.
Statement 2 is True: Australia (Great Barrier Reef), Indonesia, and the Philippines form the core of the "Coral Triangle," accounting for over a third of the world's total reef area.
Statement 3 is True: This is a fascinating ecological fact. While tropical rainforests have a vast number of *species* (mostly insects), coral reefs are vastly more diverse at the highest taxonomic level. Coral reefs host roughly 32 of the 34 known animal phyla, whereas terrestrial environments (including rainforests) only host about 9.
Route: [REALM 48: Coral Reef Ecosystems]The Marine Rainforest
The Neutral Pledge
"Momentum for Change: Climate Neutral Now" is an initiative launched by
The Secret Whisper
Official Key: (c) The UNFCCC Secretariat
The "Climate Neutral Now" initiative is part of the broader "Momentum for Change" campaign launched by the UNFCCC secretariat. It was launched in 2015 specifically to encourage individuals, companies, and governments to measure their climate footprint, reduce greenhouse gas emissions as much as possible, and offset the remainder using UN-certified emission reductions (CERs) to achieve a climate-neutral world.
Route: [REALM 200: UNFCCC]With reference to educational institutions during colonial rule in India, consider the following pairs:
| Institution | Founder |
|---|---|
| 1. Sanskrit College at Benaras | William Jones |
| 2. Calcutta Madarsa | Warren Hastings |
| 3. Fort William College | Arthur Wellesley |
Which of the pairs given above is/are correct?
The Secret Whisper
Official Key: (b) 2 only
Pair 1 is False: The Sanskrit College at Benaras was established in 1791 by Jonathan Duncan (the British Resident at Benares), not William Jones (who famously founded the Asiatic Society of Bengal).
Pair 2 is True: The Calcutta Madarsa (Aliah University today) was established by the first Governor-General, Warren Hastings, in 1781 to promote the study of Arabic and Persian.
Pair 3 is False: Fort William College (1800) was founded by Lord Richard Wellesley (the Governor-General), not Arthur Wellesley (his younger brother, the Duke of Wellington who defeated Napoleon).
Route: [REALM 60: Press & Education]The Founders' Ledger
The Fractured Map
Consider the following pairs: Regions sometimes mentioned in news vs Country
| 1. Catalonia | Spain |
| 2. Crimea | Hungary |
| 3. Mindanao | Philippines |
| 4. Oromia | Nigeria |
Which of the pairs given above are correctly matched?
The Secret Whisper
Official Key: (c) 1 and 3 only
This maps major global conflict/separatist zones that were heavily in the news.
- 1. Catalonia: A semi-autonomous region in north-eastern Spain that held a highly controversial independence referendum in 2017. (True)
- 2. Crimea: A peninsula on the Black Sea annexed by Russia from Ukraine in 2014. It has nothing to do with Hungary. (False)
- 3. Mindanao: The second-largest island in the Philippines, heavily in the news due to the siege of Marawi by ISIS-affiliated militants. (True)
- 4. Oromia: The largest regional state in Ethiopia (home to the Oromo people), embroiled in deep political protests and conflict, not Nigeria. (False)