D. Let's understand the text:

1. What accident took place at Bhopal in 1984? (ଓଡ଼ିଆ ଅର୍ଥ: ୧୯୮୪ରେ ଭୋପାଳରେ କେଉଁ ଦୁର୍ଘଟଣା ଘଟିଥିଲା?)

Ans: One of the most tragic industrial accidents took place in Bhopal on 3 December, 1984, where a deadly gas from a chemical plant escaped into the atmosphere.

2. Why is it called an industrial accident? (ଓଡ଼ିଆ ଅର୍ଥ: ଏହାକୁ କାହିଁକି ଶିଳ୍ପ ଦୁର୍ଘଟଣା କୁହାଯାଏ?)

Ans: It is called an industrial accident because the deadly gas escaped from a chemical plant (industry) operated by Union Carbide.

3. What were the tragic consequences of it? (ଓଡ଼ିଆ ଅର୍ଥ: ଏହାର ଦୁଃଖଦ ପରିଣାମ କ’ଣ ଥିଲା?)

Ans: The tragic consequences were that it killed over 4000 local residents and left a large section of the surviving population blind and crippling.

4. How is air important for man? (ଓଡ଼ିଆ ଅର୍ଥ: ମଣିଷ ପାଇଁ ବାୟୁ କିପରି ଗୁରୁତ୍ୱପୂର୍ଣ୍ଣ?)

Ans: Air is important because a man can live without food for a month, or water for days, but cannot live without breathing even for a minute.

5. What is the major source of contamination of the human body? (ଓଡ଼ିଆ ଅର୍ଥ: ମାନବ ଶରୀରର ଦୂଷିତ ହେବାର ମୁଖ୍ୟ ଉତ୍ସ କ’ଣ?)

Ans: The major source is respiration, as the quantum of pollutants that enter our body through it is manifold compared to polluted water or contaminated food.

6. What is the composition of air? (ଓଡ଼ିଆ ଅର୍ଥ: ବାୟୁର ଗଠନ କ’ଣ?)

Ans: Air is a mixture of gases comprising 78 percent nitrogen, 21 percent oxygen, less than 1 percent argon, and 0.03 percent carbon dioxide.

7. When is air said to be polluted? (ଓଡ଼ିଆ ଅର୍ଥ: ବାୟୁ କେତେବେଳେ ପ୍ରଦୂଷିତ ବୋଲି କୁହାଯାଏ?)

Ans: Air is said to be polluted if this composition is altered, such as the oxygen level getting reduced or irritating gases entering the atmosphere.

8. What fuels do the industries use? (ଓଡ଼ିଆ ଅର୍ଥ: ଶିଳ୍ପଗୁଡିକ କେଉଁ ଇନ୍ଧନ ବ୍ୟବହାର କରନ୍ତି?)

Ans: Industries use various fuels such as coal, coke, and furnace oil to produce steam.

9. How does the released smoke affect man? (ଓଡ଼ିଆ ଅର୍ଥ: ନିର୍ଗତ ଧୂଆଁ ମଣିଷକୁ କିପରି ପ୍ରଭାବିତ କରେ?)

Ans: We respire this polluted air, and without our knowledge, our lungs slowly become garbage dumps for pollutants like obnoxious gases, ash, and dust.

10. Why do thermal power stations cause more pollution? (ଓଡ଼ିଆ ଅର୍ଥ: ତାପଜ ବିଦ୍ୟୁତ୍ କେନ୍ଦ୍ରଗୁଡ଼ିକ କାହିଁକି ଅଧିକ ପ୍ରଦୂଷଣ କରନ୍ତି?)

Ans: Thermal power stations cause more pollution because they are rated first among industries that discharge high amounts of smoke and ash.

11. What are the other industries equally harmful for us ? (ଓଡ଼ିଆ ଅର୍ଥ: ଆମ ପାଇଁ ସମାନ ଭାବରେ କ୍ଷତିକାରକ ଅନ୍ୟ ଶିଳ୍ପଗୁଡ଼ିକ କ’ଣ?)

Ans: Other harmful industries include cement, steel, ore processing industries, and some chemical industries that release toxic fumes.

12. Why are the automobiles increasing on the road? (ଓଡ଼ିଆ ଅର୍ଥ: ରାସ୍ତାରେ ଯାନବାହନ କାହିଁକି ବଢୁଛି?)

Ans: Automobiles are increasing to meet the demands of an exploding population.

13. How do the automobiles contribute to air pollution? (ଓଡ଼ିଆ ଅର୍ଥ: ଯାନବାହନଗୁଡ଼ିକ ବାୟୁ ପ୍ରଦୂଷଣରେ କିପରି ଅବଦାନ ଦିଅନ୍ତି?)

Ans: Automobiles are responsible for 60 percent of air pollution as they release the maximum carbon monoxide into the atmosphere.

14. What are the effects of air pollution on vegetable crops and trees ? (ଓଡ଼ିଆ ଅର୍ଥ: ପନିପରିବା ଫସଲ ଏବଂ ଗଛ ଉପରେ ବାୟୁ ପ୍ରଦୂଷଣର ପ୍ରଭାବ କ’ଣ?)

Ans: Many flower and vegetable crops suffer ill effects from car exhaust gases, and trees have been killed by pollution from power plants.

15. How are buildings affected by polluted air? (ଓଡ଼ିଆ ଅର୍ଥ: ପ୍ରଦୂଷିତ ବାୟୁ ଦ୍ୱାରା ଅଟ୍ଟାଳିକାଗୁଡ଼ିକ କିପରି ପ୍ରଭାବିତ ହୁଅନ୍ତି?)

Ans: Fine buildings become shabby, their walls blackened with soot, and their surfaces may actually deteriorate.

16. What health problems are caused by polluted air? (ଓଡ଼ିଆ ଅର୍ଥ: ପ୍ରଦୂଷିତ ବାୟୁ ଦ୍ୱାରା କେଉଁ ସ୍ୱାସ୍ଥ୍ୟ ସମସ୍ୟା ସୃଷ୍ଟି ହୁଏ?)

Ans: Polluted air causes eye irritations, scratchy throats, and respiratory illnesses, and it also contributes to a number of serious diseases.

17. How is air pollution responsible for increasing the temperature? (ଓଡ଼ିଆ ଅର୍ଥ: ତାପମାତ୍ରା ବୃଦ୍ଧି ପାଇଁ ବାୟୁ ପ୍ରଦୂଷଣ କିପରି ଦାୟୀ?)

Ans: Gases like carbon dioxide trap the radiation that reaches the earth from the sun, and as a consequence, the atmosphere could become warmer, leading to global warming.

18. What harm can refrigerant do? (ଓଡ଼ିଆ ଅର୍ଥ: ରେଫ୍ରିଜରାଣ୍ଟ କି’ କ୍ଷତି କରିପାରେ?)

Ans: Refrigerants, which are chlorofluorocarbons (CFCs), may destroy the atmospheric layer that protects us from harmful kinds of solar energy.

19. What is acid rain ? (ଓଡ଼ିଆ ଅର୍ଥ: ଅମ୍ଳ ବର୍ଷା କ’ଣ?)

Ans: Acid rain is rain or other precipitation that contains oxides of sulphur and nitrogen, along with other chemicals.

20. How is water affected by acid rain? (ଓଡ଼ିଆ ଅର୍ଥ: ଅମ୍ଳ ବର୍ଷା ଦ୍ୱାରା ଜଳ କିପରି ପ୍ରଭାବିତ ହୁଏ?)

Ans: Acid rain causes damage in lakes and rivers, turning the water acidic and poisoning the plants and animals that live in the water.

21. What is the impact of acid rain on soil? (ଓଡ଼ିଆ ଅର୍ଥ: ମୃତ୍ତିକା ଉପରେ ଅମ୍ଳ ବର୍ଷାର ପ୍ରଭାବ କ’ଣ?)

Ans: It changes the soil's nutrient content by leaching away nutrients like potassium, calcium, and magnesium from the upper layer.

22. What are the ways to control air pollution? (ଓଡ଼ିଆ ଅର୍ଥ: ବାୟୁ ପ୍ରଦୂଷଣକୁ ନିୟନ୍ତ୍ରଣ କରିବାର ଉପାୟଗୁଡ଼ିକ କ’ଣ?)

Ans: There are three basic approaches: Preventive measures (like changing fuel ingredients), Dispersal measures (like taller smokestacks), and Collection measures (like trapping pollutants).

23. How have different countries tried to check it? (ଓଡ଼ିଆ ଅର୍ଥ: ବିଭିନ୍ନ ଦେଶ ଏହାକୁ ରୋକିବା ପାଇଁ କିପରି ଚେଷ୍ଟା କରିଛନ୍ତି?)

Ans: Nearly all highly industrialized countries have some type of legislation to prevent and control air pollution.

24. How have the air quality programmes brought us benefits? (ଓଡ଼ିଆ ଅର୍ଥ: ବାୟୁ ଗୁଣବତ୍ତା କାର୍ଯ୍ୟକ୍ରମଗୁଡ଼ିକ ଆମକୁ କିପରି ଲାଭ ଦେଇଛି?)

Ans: They have brought improvements; for example, burning low-sulfur coal and oil has lowered pollution in many cities, and new cars with catalytic converters have reduced exhaust pollution.

25. Why do we still need to find out better ways to control air pollution? (ଓଡ଼ିଆ ଅର୍ଥ: ବାୟୁ ପ୍ରଦୂଷଣକୁ ନିୟନ୍ତ୍ରଣ କରିବା ପାଇଁ ଆମକୁ କାହିଁକି ଏବେ ବି ଭଲ ଉପାୟ ଖୋଜିବାକୁ ପଡିବ?)

Ans: We still need better ways because bringing new developments is not easy, requires involvement from many experts, and costs vast sums of money.