UPSC Essentials | Daily subject-wise quiz : Environment and Geography MCQs on gases released from burning crude, microalgae

UPSC Essentialsbrings to you its initiative of subject-wise quizzes.

These quizzes are designed to help you revise some of the most important topics from the static part of the syllabus.

Attempt today’s subject quiz onEnvironment and Geographyto check your progress.

🚨Click Hereto read the UPSC Essentials magazine forFebruary 2026.Share your views and suggestions in the comment box or at manas.srivastava@indianexpress.com🚨
With reference to the microalgae-based air tower, consider the following statements:
1.

It uses photosynthetic microalgae to absorb carbon dioxide (CO₂) and nitrogen oxides (NOx).

2.

It does not absorb particulate matter (PM).

3.

Through natural bioremediation, pollutants are converted into oxygen and algal biomass in real time.

How many of the statements given above are correct?

Relevance:Microalgae-based air tower represents an emerging nature-based solution for urban air pollution control, a theme increasingly appearing in UPSC environment questions.

Such technologies are relevant for questions related to sustainable urban infrastructure, climate mitigation, and innovative environmental technologies in UPSC Prelims.

—New Delhi has commissioned India’s first microalgae-based PureAir Tower™ along the Aerocity highway corridor, marking a new experiment in science-driven urban air mitigation.

Installed on a busy central median, the structure transforms conventional road infrastructure into a functional biological air purification system.

—Unlike conventional smog towers that rely on mechanical filtration and periodic filter replacement, the PureAir Tower™ uses photosynthetic microalgae to absorb carbon dioxide (CO₂),particulate matter (PM), and nitrogen oxides (NOx) directly at street level.

Through natural bioremediation, pollutants are converted into oxygen and algal biomass in real time, with minimal energy input and no secondary filter waste.Hence, statements 1 and 3 are correct and statement 2 is not correct.

Therefore, option (b) is the correct answer.

With reference to the Western Disturbances, consider the following statements:
1.

They are east-moving rain-bearing wind systems that originate beyond Iran.

2.

It cause heavy rainfall in southern India, especially overTamil Naduand Kerala.

3.

They are common in summer months.

Relevance:Western Disturbance is a key topic in Indian climatology, frequently asked in UPSC Prelims through statement-based questions.

It is also important for linking winter rainfall, snowfall, and rabi crop productivity in northwestern India in geography and environment questions.

—In its March forecast, the IMD said that day temperatures over western Himalayan regions and peninsular and central India would remain ‘above’ normal.

It also warned of ‘above’ normal heatwave days in Gujarat and Andhra Pradesh.

Both scenarios were realised within the very first week of March.

—A state like Himachal Pradesh has already experienced temperatures above 25 degrees Celsius.

A similar situation prevailed inJammuand Kashmir and Ladakh last week.

—Western Disturbances are east-moving rain-bearing wind systems that originate beyond Iran, and pick up moisture from the Mediterranean Sea and other water bodies.Hence, statement 1 is correct.

—Theirmajor impact is over north and north-western India and the Himalayas, not southern states like Tamil Nadu or Kerala.Hence, statement 2 is not correct.

—They are common inwinter months.

Hence, statement 3 is not correct.

Therefore, option (a) is the correct answer.

When an oil well or depot is struck by a missile or ignited by explosives, the results are immediate and catastrophic.

Burning crude releases toxic gases, which includes:
Select the correct answer using the codes given below:
Relevance:Burning of Crude Oil releases toxic pollutants, making it relevant for environment and pollution-based UPSC Prelims questions.

Such issues often appear in the context of conflicts like the Gulf War, where burning oil wells caused severe air pollution.

—When an oil well or depot is struck by a missile or ignited by explosives, the results are immediate and catastrophic.Burning crude releases a toxic cocktail of gases —sulphur dioxide, carbon monoxide, hydrogen sulfide, and nitrogen oxides.Not just these,dense clouds of soot, packed with partially burned hydrocarbons and heavy metals are also released, which significantly spike the pollution in a particular region.

— Ozone is not directly emitted from burning crude; it forms secondarily in the atmosphere while chlorine is not released from crude oil combustion.

—These plumes don’t just rise harmlessly into the upper atmosphere; they spread at ground level, embedding themselves in soil, water… and human lungs.

With reference to the cycads, consider the following statements:
1.

These plants can raise their own temperature.

2.

Cycads are mainly pollinated by butterflies.

Which of the statements given above is/are correct?

Relevance:Cycads are important in plant taxonomy and evolution, a recurring theme in UPSC Prelims environment and biodiversity questions.

Their unique traits like thermogenic cones and insect pollination are often used by UPSC to frame statement-based conceptual MCQs on plant biology and biodiversity.

—Theplant kingdom is utterly fascinating and still has a lot to be discovered.

From plants that can attack animals to those that give electric shocks, these botanicals are far from fully understood.

One such plant species that has created waves in the botanical community is cycads.

—These ancient plants can raise their own temperature.

As these plants heat themselves up, an invisible signal is released that helps insects find them in the dark.Hence, statement 1 is correct.

—Cycads have existed on Earth since the time of dinosaurs and are often described as “living fossils.

Unlike modern flowering plants that depend on bees or butterflies,cycads are mainly pollinated by beetles.Hence, statement 2 is not correct.

Which of the following countries are divided along the Aras river — both a natural and a modern-day geopolitical boundary?

Relevance:The Aras River is an important international boundary river in the Caucasus region, which can appear in map-based questions in UPSC Prelims.

Understanding rivers forming boundaries will help in solving geopolitical and location-based MCQs.

—Modern interaction betweenIran and Azerbaijan, home to two of the world’s largest Shia populations, is characterised by a root difference between them.

While Iran transformed into a Shia theocracy following the 1979 Islamic Revolution, Azerbaijan adopted a strict secularism in 1991 after the dissolution of the erstwhile Soviet Union — which Iran viewed as a Western-oriented governance model.

—Divided along the Aras river — both a natural and a modern-day geopolitical boundary — since the 1828 Treaty of Turkmenchay, the Azeris (as the people of Azerbaijan are called) have been historically sandwiched between Russian and Persian culture.

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