Explanation:

• Statement 1 is correct: Pyrolysis involves heating materials without oxygen at high temperatures.
• Statement 2 is correct: Pyrolysis was proposed to convert PPE kits into biofuel during the COVID-19 pandemic.
• Statement 3 is incorrect: Pyrolysis reduces GHG emissions and minimizes water pollution risks.

Improper Use of Pyrolysis:

• • Pyrolysis involves breaking down materials at high temperatures without oxygen.
  • Sub-optimal pyrolysis technologies in many industrial units leave residues like fine carbon matter, pyro gas, and oil.

Applications of Pyrolysis:

• • Produces methanol, activated carbon, and charcoal from wood in the chemical industry.
  • Generates synthetic gas for electricity production in gas turbines.
  • Recycles pyrolytic waste into building materials.
  • Converts disposable COVID-19 PPE kits into biocrude synthetic fuel.

Advantages of Pyrolysis:

• • Cost-effective for processing various feedstocks.
  • Reduces landfill waste and greenhouse gas emissions.
  • Minimizes the risk of water pollution.

Regulations:

• • The National Green Tribunal banned the burning of used tires in the open and their use as fuel in brick kilns in 2014.

Explanation:

• Statement 1: Correct. Noise is measured in decibels (dB), which represent the loudness of sound.
• Statement 2: Incorrect. The WHO prescribes an optimum noise level of 45 dB during the day and 35 dB at night, not 55 dB and 45 dB.
• Definition of Noise Pollution: Any unwanted sound that causes annoyance, irritation, and pain to the human ear.
• Measurement: Noise is measured in decibels (dB), which indicates the loudness of the sound.
• WHO Guidelines: The World Health Organization prescribes an optimum noise level of 45 dB during the day and 35 dB at night.
• Human Tolerance: The human ear can tolerate noise levels up to 85 dB without adverse effects.
• Hazardous Noise Levels: Sound above 80 dB is considered loud and potentially hazardous to health.
• Uncomfortable Noise Levels: Sound between 100-125 dB is deemed uncomfortable for human hearing.

Explanation:

• Fly ash contains toxic heavy metals such as lead, mercury, cadmium, arsenic, cobalt, and copper. However, sodium is not a major component of fly ash.

Explanation:

• Statement 1 is correct: NPs form dust clouds that reduce sunlight intensity and affect visibility.
• Statement 2 is correct: NPs bind with hydroxyl radicals, reducing their ability to cleanse pollutants.
• Statement 3 is incorrect: NPs do not contribute to ozone formation; they facilitate ozone depletion.
• Size of Nanoparticles (NPs): Nanoparticles are extremely small, measuring about 1/10^9 of a meter.
• Natural Sources: Major natural processes releasing NPs include forest fires, volcanic eruptions, weathering, and dust storms.
• Transport and Suspension: Naturally occurring NPs can travel thousands of kilometers and remain suspended in the air for several days.

Reactivity and Environmental Impact:

• • NPs have large surface area to volume ratios, enhancing their reactivity in the atmosphere.
  • They can grow into particles large enough to interact with radiation, affecting visibility and climate.

Applications of Nanotechnology:

• • Nanotechnology has significant global socioeconomic value with applications in electronics, biomedical fields, and more.
  • Human-made NPs are released into the environment during various industrial and mechanical processes.

Effects on the Environment:

• • Dust Cloud Formation: NPs can coagulate to form dust clouds, reducing sunlight intensity and affecting glaciers by depositing soot and black carbon.
  • Interaction with Hydroxyl Radicals: NPs bind with hydroxyl radicals in the troposphere, reducing the atmosphere’s natural capacity to scrub pollutants.
  • Ozone Depletion: NPs can increase the production of free radicals which destroy ozone.
  • Stratospheric Temperature: Interaction of NPs with molecular hydrogen can lead to increased water vapor in the stratosphere, potentially causing stratospheric cooling and additional ozone depletion through the formation of stratospheric clouds.

Explanation:

• Statement 1 is correct: Black carbon is short-lived, staying in the atmosphere for days to weeks before being washed out.
• Statement 2 is correct: When black carbon settles on ice or snow, it darkens the surface, reducing reflectivity (albedo), which accelerates melting.
• Statement 3 is correct: India and China are the largest global contributors to black carbon emissions.

Black carbon

• Black Carbon (BC), also known as soot, is a particulate matter resulting from incomplete combustion.
• Acts as a short-lived air pollutant affecting regional cloudiness and monsoon rainfall.
• Strong absorber of sunlight, significantly more than carbon dioxide, heating the air directly.
• When deposited on snow, reduces albedo, leading to increased melting of ice and snow.
• Lifespan in the atmosphere ranges from days to weeks, with effects dissipating months after emission reduction.
• Major Emitters: India and China are the largest global sources of black carbon.
• Indo-Gangetic Plain predicted to become a major source, with emissions from biofuels (20%), fossil fuels (40%), and biomass burning (40%).

Explanation:

• Statement 1 is correct: Stratospheric ozone (good ozone) is formed due to the interaction between oxygen (O₂) and ultraviolet (UV) radiation, preventing harmful UV rays from reaching Earth.
• Statement 2 is correct: Tropospheric ozone (bad ozone) is formed through photochemical reactions involving pollutants like NOx and VOCs, making it a short-lived greenhouse gas.
• Statement 3 is correct: Ground-level ozone is produced when nitrogen oxides (NOx) and volatile organic compounds (VOCs) react with sunlight, leading to ozone formation through photochemical reactions.
• Ozone (O3) constitutes less than 0.00005% by volume of the atmosphere, unevenly distributed.
• Stratospheric Ozone (Good Ozone): Formed by the interaction of O2 and UV light, absorbs harmful ultraviolet rays.
• Ground-Level Ozone (Bad Ozone): Acts as a pollutant and short-lived greenhouse gas with toxic effects, not emitted directly but formed by air pollutants’ reaction under sunlight.

Ozone Formation at Ground Level:

• Carbon Monoxide reacts with hydroxyl radical (-OH) to produce hydroperoxy radical (HO2).
• Volatile Organic Compounds react with hydroxyl radical (-OH) to produce peroxy radical (RO2).
• Hydroperoxy radicals react with Nitrogen Oxide (NO) to form NO2 and regenerate hydroxyl radical (OH) or produce alkoxy radical (RO).
• NO2 undergoes photolysis to yield O3 (ozone).

Explanation:

• Statement 1 is correct: NOx gases are primarily produced from vehicle exhaust, coal-fired power plants, and industrial combustion.
• Statement 2 is correct: NO and NO₂ contribute to global cooling, while N₂O acts as a greenhouse gas.
• Statement 3 is incorrect: Oxygen and nitrogen do not react at normal temperatures; they require high temperatures, such as those in combustion engines or power station boilers, to form nitrogen oxides.
• NOx refers to various nitrogen oxides produced during combustion, primarily in internal combustion engines and coal-burning power plants.
• Natural Production: Also produced by lightning, and from agricultural fertilization and nitrogen-fixing plants through microbial N-fixation.
• Formation Conditions: Oxygen and nitrogen react to form NOx at high temperatures, such as those found in combustion engines or power station boilers.
• Components of NOx: Includes Nitric Oxide (NO – colorless, odorless gas) and Nitrogen Dioxide (NO2 – reddish-brown gas with a pungent odor). Other nitrogen oxides include Nitrogen Trioxide (NO3), Nitrous Oxide (N2O), Dinitrogen Tetroxide (N2O4), and Dinitrogen Pentoxide (N2O5).
• Environmental Impact: Nitrogen Oxide (NO) and Nitrogen Dioxide (NO2) contribute to global cooling. Not to be confused with Nitrous Oxide (N2O), a greenhouse gas used as an oxidizer.

Explanation:

• Singrauli, Madhya Pradesh – Correct; a major thermal power hub.
• Neyveli, Tamil Nadu – Correct; home to a large lignite-based power station.
• Jaipur, Rajasthan – Incorrect; not listed as a major SO₂ emission hotspot.
• Talcher, Odisha – Correct; a significant coal-based thermal power station.
• India’s SO2 Emissions: Accounts for more than 15% of all anthropogenic sulphur dioxide (SO2) hotspots detected globally.
• Detection Method: Identified using the Ozone Monitoring Instrument (OMI) satellite.

Major Hotspots in India:

• Singrauli, Madhya Pradesh
• Neyveli and Chennai, Tamil Nadu
• Talcher and Jharsuguda, Odisha
• Korba, Chhattisgarh
• Kutch, Gujarat
• Ramagundam, Telangana
• Chandrapur and Koradi, Maharashtra

Explanation:

• Statement 1 – Correct; Formaldehyde is widely used in building materials like plywood and particleboard.
• Statement 2 – Correct; It is used as a fungicide, germicide, and disinfectant.
• Statement 3 – Correct; It occurs naturally in decaying plant material.
• Statement 4 – Incorrect; It is not used as a combustion fuel in vehicles.

Uses of Formaldehyde:

• Commonly found in building materials like particleboard, plywood, and pressed-wood products.
• Used as a fungicide, germicide, disinfectant, and preservative in mortuaries and laboratories.

Natural Occurrence:

• Naturally occurs in the environment.
• Produced during the decay of plant material in soil and through chemical processes in living organisms.

Combustion Product:

• Present in tobacco smoke as a byproduct of combustion.

Explanation:

1. Cosmic Rays – These are high-energy radiations originating from outer space, contributing to natural radiation exposure on Earth.
2. Nuclear Power Plant Leaks – Accidental leaks from nuclear reactors release radioactive isotopes into the environment, leading to artificial radioactive pollution.
3. Mining of Uranium and Thorium – Extraction of radioactive minerals such as uranium (used in nuclear reactors) and thorium (monazite ore) exposes workers and the environment to radiation hazards.
4. Nuclear Fallout – Nuclear weapon testing and explosions release radioactive substances like Strontium-90, Cesium-137, and Iodine-131, which contaminate air, water, and soil.

• Radioactivity: Spontaneous emission of protons (alpha-particles), electrons (beta-particles), and gamma rays (short-wave EMR) from atomic nuclei disintegration.
• Radiation Categories: Non-ionizing and ionizing radiations.
• Radioactive Pollution: Increase in environmental radiation levels causing severe threats to humans and other life forms.
• Radioactive Contamination: Presence of radioactive substances in undesirable locations, including on surfaces or within solids, liquids, or gases.
• Natural Radiation Sources: Cosmic rays from space and terrestrial radiations from radionuclides in the earth’s crust (e.g., radium-224, uranium-238, thorium-232, potassium-40, carbon-14).
• Artificial Radiation Pollution: Caused by accidental leaks from nuclear power plants, unsafe radioactive waste disposal, nuclear weapon testing, and nuclear fallout containing strontium-90, caesium-137, iodine-131.
• Mining and Medical Exposure: Includes mining of radioactive materials like uranium and thorium (monazite ore), and medical exposures such as X-rays, CT scans, chemotherapy.
• Slow Nuclear Radiations: Emanate from nuclear reactors, laboratories, and other facilities handling radioactive materials.

Explanation:

• Combustion of oil, coal, gas produces NO and NO₂ from industrial and vehicular emissions.
• Bacterial action in soil releases nitrogen oxides naturally.
• Forest fires and volcanic activity also contribute to nitrogen oxides.
• Evaporation of fuels is related to VOCs (Volatile Organic Compounds), not nitrogen oxides.

Nitrogen Oxides (NO and NO2):

• Sources: Combustion of oil, coal, gas; bacterial action in soil; forest fires; volcanic action; lightning.
• Effects: Decreased visibility due to yellowish color of NO2; suppression of plant growth.

Explanation:

• Respiratory irritation, eye irritation, and carcinogenic effects are caused by VOCs.
• Breaks down rubber is an effect of ozone (O₃), not VOCs.

Volatile Organic Compounds (VOCs):

• Sources: Evaporation of fuels; incomplete combustion of fossil fuels.
• Effects: Eye irritation; respiratory irritation; some compounds are carcinogenic; decreased visibility due to blue-brown haze.

Ozone (O3):

• Formation: From photolysis of NO2; sometimes from stratospheric ozone intrusions.
• Effects: Decreased crop yields; retardation of plant growth; damage to plastics; breakdown of rubber.

Explanation:

• Electrostatic Precipitators (ESP) are used in thermal power plants, cement factories, and steel plants to remove over 99% of particulate matter by charging dust particles and collecting them on an oppositely charged surface.

Explanation:

1. PM2.5 and PM10 – SAFAR monitors these as primary air quality indicators.
2. Ozone (O₃) and Carbon Monoxide (CO) – Both are included in SAFAR’s pollutant monitoring system.
3. Sulphur Dioxide (SO₂) and Nitrogen Oxides (NOx) – These major gaseous pollutants are tracked by SAFAR.
4. Benzene and Mercury – SAFAR also monitors these due to their harmful effects on health and the environment.

Pollutants monitored under the SAFAR System

• PM2.5
• PM10
• Ozone
• Carbon Monoxide (CO)
• Nitrogen Oxides (NOx)
• Sulphur Dioxide (SO2)
• Benzene: Found in crude oil, used in plastics, resins, synthetic fibers; reacts with other pollutants to form ground-level ozone, damaging crops and materials.
• Toluene (methylbenzene): Used in paint thinners, octane booster in gasoline engines.
• Xylene (dimethylbenzene): Solvent in printing, rubber, and leather industries.

Explanation:

• A catalytic converter is used in automobiles to reduce poisonous gas emissions. It contains platinum-palladium and rhodium catalysts and requires unleaded petrol, as lead in petrol deactivates the catalyst.

Explanation:

• Sulphur Oxides (SOₓ): Major contributors to acid rain as they react with water to form sulphuric acid (H₂SO₄).
• Nitric Oxide (NO) & Nitrogen Dioxide (NO₂): These react with water to form nitric acid (HNO₃), leading to acid rain.
• Nitrous Oxide (N₂O): While a greenhouse gas, it does not significantly contribute to acid rain formation.

Explanation:

1. Red Category → 60+ (Critically Polluted)
   • Industries falling under this category are considered critically polluted and require strict environmental regulations.
2. Orange Category → 41 to 59 (Severely Polluted)
   • These industries are considered severely polluted but not as harmful as the Red category.
3. Green Category → 21 to 40 (Other Polluted)
   • These industries have moderate pollution levels and require some level of environmental regulation.
4. White Category → 0 to 20 (Practically Non-Polluting)
   • Newly introduced, industries under this category do not require Environmental Clearance (EC) or Consent to Operate but must notify SPCB (State Pollution Control Board) and CPCB (Central Pollution Control Board).

Explanation:

• The Cyclone, a type of Inertial Collector, removes heavier particulate matter from gas streams using centrifugation. It is commonly used in gas cleaning plants to separate dust and debris efficiently.

Explanation:

• Statement 1 is correct: ISA was launched by India and France at COP21 in Paris in 2015.
• Statement 2 is incorrect: Countries outside the tropics can join but do not have voting rights.

International Solar Alliance (ISA)

• ISA (International Agency for Solar Policy and Application): Treaty-based intergovernmental organization focused on efficient solar energy use to reduce fossil fuel dependence.
• Proposal and Launch: Proposed by PM Modi at the India Africa Summit, launched with France at the 2015 UNFCCC (COP21, Paris) through the Paris Declaration.
• Headquarters: Located in Gurugram, India.
• Membership: Originally an alliance of 123 sunshine countries within the Tropic of Cancer and the Tropic of Capricorn. Non-tropical countries can join without voting rights. As of February 2023, 92 countries have ratified the ISA Framework Agreement.
• Operational Focus: Aims to complement and synergize with existing efforts rather than duplicating them, focusing on establishing networks and developing sustainable partnerships.
• Global Partnerships: Collaborates with multilateral development banks (MDBs), development financial institutions (DFIs), and international institutions like International Renewable Energy Agency (IRENA), Renewable Energy and Energy Efficiency Partnership (REEEP), International Energy Agency (IEA), Renewable Energy Policy Network for the 21st Century (REN21), and various United Nations bodies.

Explanation:

• IRENA, REEEP, and IEA are ISA partners.
• IAEA (International Atomic Energy Agency) is not related to ISA, as it primarily deals with nuclear energy.

Explanation:

• The World Bank is providing technical assistance to develop the OSOWOG blueprint, which supports the deployment of grid-connected rooftop solar installations and other solar energy initiatives.

Explanation:

• Bioethanol is a liquid biofuel derived from organic matter. Other examples include biodiesel, while wood (solid) and biogas (gaseous) are other forms of biofuels.

Explanation:

• Biofuels emit less CO₂ than conventional fossil fuels, making them an eco-friendly alternative. They can also be blended with existing fuels to help reduce carbon emissions in the transport sector.

Explanation:

• Statement 1: Correct. The National Policy on Biofuels-2018 sets an indicative target of 20% ethanol blending in petrol and 5% blending of biodiesel in diesel by 2030.
• Statement 2: Incorrect. Ethanol blending under the EBP programme is carried out by Oil Marketing Companies (OMCs), not the Ministry of New and Renewable Energy.

Explanation:

• RE-Invest 2024 aligns with SDG 7 (Affordable and Clean Energy) by promoting renewable energy solutions and SDG 13 (Climate Action) by supporting initiatives that reduce carbon emissions and combat climate change.

Explanation:

• Statement 1: Correct. The Sustainable Alternative Towards Affordable Transportation (SATAT) scheme was launched in 2018 by the Ministry of Petroleum and Natural Gas.
• Statement 2: Incorrect. Entrepreneurs, not OMCs, set up CBG plants and supply compressed biogas (CBG) to OMCs for sale as an alternative fuel.
• Sustainable Alternative Towards Affordable Transportation (SATAT) launched in 2018 by the Ministry of Petroleum and Natural Gas with PSU Oil Marketing Companies like Indian Oil Corporation Ltd.
• Entrepreneurs to set up CBG (Compressed Biogas) plants under SATAT to produce and supply CBG to Oil Marketing Companies for sale as alternative, green automotive and industrial fuel.

Benefits of SATAT:

• Tackles urban air pollution from farm stubble-burning and reduces carbon emissions.
• Enhances farmers’ income, promotes rural employment, and fosters entrepreneurship.
• Efficient treatment/disposal of municipal solid waste.
• Promotes organic farming through the use of Fermented Organic Manure (FOM) from CBG plants.
• Provides a buffer against crude oil/gas price fluctuations.

Explanation:

As of August 2024, the installed capacity for different renewable energy sources in India is:

• Solar Power → 89.43 GW (Highest)
• Wind Power → 47.19 GW
• Large Hydro → 46.92 GW
• Biomass/Cogeneration → 10.35 GW
• Thus, the correct descending order is Solar Power > Wind Power > Large Hydro > Biomass/Cogeneration.

Explanation:

• India is leading the RE-Invest 2024 platform, organized by the Ministry of New and Renewable Energy (MNRE), to promote collaboration, investment, and innovation in the renewable energy sector.

Explanation:

• Statement 1: Correct. Petro crops, including Jatropha curcas, can be grown on land unsuitable for agriculture and forest cover.
• Statement 2: Incorrect. Biocrude from Jatropha curcas can be hydrocracked to produce gasoline, gas oil, and kerosene.Top of Form

Explanation:

• Statement 1: Correct. The Puga Valley in Ladakh is considered the most promising geothermal site in India.
• Statement 2: Incorrect. India has identified potential geothermal sites, but commercial geothermal electricity production is not yet widespread.