UPPCS Prelims 2018 · GS Paper I: A powerful eye irritant in the smoke is
A powerful eye irritant in the smoke is
Answer (d) & explanation
Option (d) is right: peroxyacetyl nitrate (PAN), formed in photochemical smog, is a powerful eye irritant, or lachrymator, and is the main cause of watering and burning eyes in smog. Option (a), ozone, is also a smog component; it mainly irritates the lungs and damages plants, but is less of an eye irritant than PAN. Option (b), sulphur dioxide, mainly irritates the respiratory tract and causes acid rain. Option (c), carbon dioxide, is not an irritant at normal levels; it is a greenhouse gas. Concept: photochemical smog forms when nitrogen oxides and hydrocarbons from vehicle exhaust react in sunlight, and it peaks on warm, sunny afternoons. PAN and ozone are secondary pollutants, made in the air rather than emitted directly.
Ozone is the famous smog gas, but the strongest eye irritant is PAN.
Question as printed in UPPSC's official question booklet. Source: uppsc.up.nic.in
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Same theme in UPSC Mains
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Related questions from other years
Which of the following statements with regard to Green Hydrogen is/are correct ?
- 1. It is decarbonized hydrogen obtained from natural gas reforming combined with carbon capture and storage (CCS).
- 2. It is produced using electrolysis of water with electricity generated by renewable energy.
- 3. National Green Hydrogen Mission of India aims for abatement of nearly 50 MMT of annual greenhouse gas emissions by 2030.
Select the answer using the code given below :
Answer (b) & explanation
Statements 2 and 3 are correct (b). Statement 2 is right: green hydrogen comes from splitting water by electrolysis, using renewable power. Statement 3 is right: the National Green Hydrogen Mission (2023) targets 5 MMT of green hydrogen a year by 2030 and about 50 MMT of avoided CO₂-equivalent emissions each year. Statement 1 is wrong: hydrogen from natural gas with carbon capture is blue hydrogen. So options (a), (c) and (d) fail.
Notice the colours: grey hydrogen from gas without capture (most hydrogen today), brown from coal, and pink from nuclear power. The mission's SIGHT programme supports electrolyser making. Uses include fertilisers, refineries, steel and shipping fuel.
1 says "decarbonized", which sounds green. Gas with CCS is blue.
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Answer as per the official UPSC answer key.
Which of the following statements in relation to NIRANTAR (National Institute for Research and Application of Natural Resources to Transform, Adapt and Build Resilience), a platform of institutions under the Ministry of Environment, Forest and Climate Change, is/are correct ?
- 1. Ecosystem Survey and Analysis is a vertical under this platform, the lead institute of which is Botanical Survey of India, Kolkata.
- 2. Research and Management of Ecosystem Service is a vertical under this platform, the lead institute of which is Central Zoo Authority, New Delhi.
- 3. Capacity Development Support is a vertical under this platform, the lead institute of which is Indian Institute of Forest Management, Bhopal.
Select the answer using the code given below :
Answer (b) & explanation
Statements 1 and 3 are correct (b). NIRANTAR groups the Environment Ministry's institutes into verticals. Statement 1 is right: Ecosystem Survey and Analysis is led by the Botanical Survey of India, Kolkata, with bodies like the FSI and ZSI. Statement 3 is right: Capacity Development Support is led by the Indian Institute of Forest Management, Bhopal. Statement 2 is wrong: Research and Management of Ecosystem Service is led by ICFRE, Dehradun; the Central Zoo Authority is only a member. So options (a), (c) and (d) fail.
Notice the purpose: pooling institutes avoids duplicate work and links research to climate adaptation and resilience. Other Ministry bodies include the Wildlife Institute of India (Dehradun) and GBPNIHE for the Himalaya.
the Central Zoo Authority does sit in that vertical, but as a member, not the lead.
Answer as per the official UPSC answer key.
Consider the following statements with reference to India’s response to climate change :
- I. India’s Long-Term Low Emission Development Strategy (LT-LEDS) is a crucial tool for achieving net-zero emissions by 2070.
- II. India’s 4th Biennial Update Report (BUR-4) submitted in December, 2024 recorded around 8% decrease in Greenhouse gas emissions in 2020 over 2019.
- III. Climate-resilient development necessarily depends on quick and short-term achievement of emission reduction targets.
Which of the following relationships among the above statements is/are correct ?
- 1. Statement I is empirically supported by statement II.
- 2. Statement III contradicts the approach implicit in statement I.
- 3. Statement I and statement III together establish the premise of long-term sustainability.
Select the answer using the code given below :
Answer (b) & explanation
Relationships 1 and 2 are correct (b). Relationship 1 is right: the LT-LEDS (2022) lays out India's path to net zero by 2070, and BUR-4 reported a fall of about 7.9% in 2020 emissions over 2019, real data in line with that path. Relationship 2 is right: Statement III wants quick, short-term cuts, while the LT-LEDS is a long, gradual plan, so III contradicts I. Relationship 3 is wrong: two contradicting statements cannot together set a premise. So options (a), (c) and (d) fail.
Notice the cause of the 2020 fall: the COVID-19 lockdowns, not a lasting trend. India's updated NDC (2022) targets cutting emissions intensity of GDP by 45% from 2005 levels by 2030. Biennial Transparency Reports now replace BURs.
"together establish" sounds positive, but two statements that clash cannot form one premise.
Answer as per the official UPSC answer key.
With respect to the Western Hoolock Gibbons, which of the following statements is/are correct ?
- 1. A Sanctuary in North-east India is home to this ape species listed as Endangered in the International Union for Conservation of Nature (IUCN) Red List.
- 2. They have specialized brachiation and can easily swing between trees.
- 3. They possess a strong and heavy build like gorillas, yet are remarkably agile tree climbers.
Select the answer using the code given below :
Answer (b) & explanation
Statements 1 and 2 are correct (b). Statement 1 is right: India's only ape, the western hoolock gibbon, is Endangered on the IUCN Red List and gives its name to the Hollongapar Gibbon Sanctuary in Assam. Statement 2 is right: gibbons move by brachiation, swinging arm over arm through the canopy. Statement 3 is wrong: they are "lesser apes", slim and light, about 6–9 kg, nothing like a heavy gorilla. So options (a), (c) and (d) fail.
Notice their habits: they live in pairs with their young and sing loud duets at dawn. They are found south of the Brahmaputra in the North-East. Rail lines cutting through Hollongapar have raised concern, and canopy bridges were proposed to help them cross.
Answer as per the official UPSC answer key.