All questions of Environmental Issues for UPSC CSE Exam

**Water Pollution and Disease**

Water pollution refers to the contamination of water bodies, such as rivers, lakes, and oceans, with harmful substances. These substances can come from various sources, including industrial waste, sewage, agricultural runoff, and chemical spills. Water pollution has detrimental effects on both the environment and human health. In the case of human health, water pollution can lead to the spread of various diseases.

**Diarrhea: A Waterborne Disease**

One of the diseases caused by water pollution is diarrhea. Diarrhea is characterized by the frequent passage of loose or watery stools. It is a common illness that affects people of all ages, particularly children under the age of five. Diarrhea is a leading cause of morbidity and mortality worldwide, especially in developing countries where access to clean and safe water is limited.

**How Water Pollution Causes Diarrhea**

Water pollution can contribute to the spread of diarrheal diseases in several ways:

1. **Contamination with Pathogens**: When water bodies become polluted with fecal matter, they can become reservoirs for disease-causing pathogens such as bacteria, viruses, and parasites. These pathogens can enter the human body when contaminated water is ingested, leading to the development of diarrhea.

2. **Chemical Contaminants**: Water pollution can also introduce various chemical contaminants into water bodies. These contaminants may include heavy metals, pesticides, and industrial chemicals. Exposure to these chemicals through contaminated water can irritate the digestive system and contribute to the development of diarrhea.

3. **Inadequate Sanitation**: Water pollution often occurs due to inadequate sanitation practices, such as the improper disposal of sewage and wastewater. When human waste is not properly treated or disposed of, it can contaminate water sources and increase the risk of diarrheal diseases.

**Prevention and Control**

Preventing water pollution is crucial in reducing the incidence of waterborne diseases like diarrhea. Some measures that can be taken to prevent water pollution and ensure access to clean and safe water include:

- **Proper Waste Management**: Implementing proper waste management systems, including the treatment and safe disposal of sewage and wastewater, can prevent the contamination of water bodies.

- **Improved Sanitation**: Providing access to adequate sanitation facilities, such as toilets and handwashing stations, can prevent the spread of diarrheal diseases.

- **Water Treatment**: Implementing effective water treatment methods, such as filtration, disinfection, and chlorination, can help remove pathogens and chemical contaminants from water sources.

- **Public Awareness and Education**: Promoting awareness and educating communities about the importance of clean water, proper sanitation, and hygiene practices can help prevent water pollution and reduce the incidence of waterborne diseases.

In conclusion, water pollution can contribute to the spread of various diseases, including diarrhea. It is essential to implement measures to prevent water pollution and ensure access to clean and safe water for the well-being of individuals and communities.

Ozone Holes: More Pronounced at the Poles

Introduction:
Ozone holes are areas in the Earth's ozone layer where the concentration of ozone becomes significantly depleted. These ozone holes are caused by the release of certain chemicals, such as chlorofluorocarbons (CFCs), which break down ozone molecules in the stratosphere. The depletion of the ozone layer allows more harmful ultraviolet (UV) radiation from the Sun to reach the Earth's surface, posing risks to human health and the environment.

Explanation:
The ozone holes are more pronounced at the poles due to several factors:

1. Atmospheric conditions:
At the poles, the stratospheric conditions are more favorable for the formation of ozone holes. During winter, the polar regions experience a phenomenon called polar vortex, where a strong, stable, and cold air mass forms a swirling pattern. This vortex isolates the polar regions from the rest of the atmosphere, trapping the air and preventing it from mixing with air from lower latitudes. As a result, the polar regions experience extremely low temperatures, which contribute to the formation of polar stratospheric clouds (PSCs). PSCs provide the surface for chemical reactions that break down ozone molecules.

2. Presence of CFCs:
Chlorofluorocarbons (CFCs) and other ozone-depleting substances released by human activities accumulate in the stratosphere. These substances can remain in the atmosphere for several decades, gradually drifting towards the poles due to atmospheric circulation patterns. As a result, the concentration of CFCs is higher at the poles compared to other latitudes. When exposed to UV radiation, CFCs release chlorine atoms that catalytically destroy ozone molecules.

3. Polar night:
During the polar winter, the polar regions experience an extended period of darkness known as polar night. The absence of sunlight during this period allows the formation of stable polar stratospheric clouds. These clouds provide a surface for chemical reactions involving CFCs and other ozone-depleting substances, leading to an accelerated depletion of ozone.

4. Stratospheric winds:
The polar regions are influenced by strong stratospheric winds, known as polar vortex winds, which circulate around the poles. These winds contribute to the isolation of the polar regions and prevent the mixing of air masses from lower latitudes, leading to the persistence of low temperatures and the accumulation of ozone-depleting substances.

Conclusion:
In conclusion, ozone holes are more pronounced at the poles due to a combination of favorable atmospheric conditions, the presence of ozone-depleting substances, the occurrence of polar night, and the influence of polar vortex winds. These factors contribute to the localized depletion of ozone in the polar regions, making them more vulnerable to the harmful effects of UV radiation.

Meaning of Denial of Forest

Denial of forest refers to the act of destroying or degrading a forest, which leads to its disappearance or reduction in size. This can happen due to various reasons such as urbanization, deforestation for agricultural purposes, mining, logging, and industrialization. The consequences of this denial of forest are quite severe, and they can affect the environment, wildlife, and people in several ways.

Consequences of Denial of Forest

1. Loss of biodiversity: Forests are home to a diverse range of plant and animal species. When forests are destroyed, many species lose their habitat, and their populations decline or become extinct.

2. Climate change: Forests play a crucial role in regulating the Earth's climate. They absorb carbon dioxide from the atmosphere, which helps to mitigate the effects of climate change. When forests are destroyed, this carbon dioxide is released back into the atmosphere, contributing to global warming and climate change.

3. Soil erosion: Forests help to prevent soil erosion by holding the soil together with their roots. When forests are destroyed, the soil becomes exposed to wind and water erosion, which can lead to land degradation and desertification.

4. Water cycle disruption: Forests play a vital role in the water cycle by absorbing rainwater and releasing it slowly into the soil and atmosphere. When forests are destroyed, this water cycle is disrupted, leading to reduced water availability, droughts, and floods.

5. Impact on indigenous people: Many indigenous people depend on forests for their livelihoods and cultural practices. When forests are destroyed, these people lose their way of life and can become displaced and marginalized.

Conclusion

Denial of forest has significant consequences for the environment, wildlife, and people. It is essential to take steps to prevent further forest destruction and promote afforestation and reforestation efforts. This can help to mitigate the effects of climate change, protect biodiversity, and preserve indigenous cultures and ways of life.

Boiling Point Elevation

Boiling point is defined as the temperature at which the vapor pressure of a liquid equals the atmospheric pressure surrounding it. When a solute such as salt or sugar is added to water, it lowers the vapor pressure of the water, which means it takes longer for the water to boil. This phenomenon is known as boiling point elevation.

Explanation of the Answer

When impurities such as salt or sugar are added to pure water, the boiling point of the resulting solution increases. This is because the presence of the solute lowers the vapor pressure of the solution, which means more heat is required to reach the boiling point. This is why we add salt to water when boiling pasta, as the higher boiling point allows the pasta to cook more evenly.

Therefore, in comparison to pure water, the boiling point of impure water increases. This is because the impurities in the water lower the vapor pressure, which means more heat is required to reach boiling point.

DDT and Bird Population Decline

Introduction:
DDT or Dichloro-Diphenyl-Trichloroethane is an insecticide that was widely used in the mid-20th century to control agricultural pests and diseases that spread through insects. It is a persistent organic pollutant that accumulates in the food chain, causing adverse effects on human and animal health. DDT was banned in most countries in the 1970s due to its harmful effects on the environment.

Effect of DDT on Bird Population:
DDT is known to cause a decline in the population of birds that feed on insects, such as eagles, falcons, and ospreys. This is due to the fact that DDT affects the reproductive system of birds, leading to a decline in their egg production and hatching rates.

Eggshell Thinning:
DDT causes the eggshells of birds to become thin, making them more susceptible to breakage. When birds lay their eggs, the shells are too thin to withstand the weight of the incubating parent, leading to the death of the embryo inside. This phenomenon is known as eggshell thinning, and it has been observed in several bird species, including Bald Eagles, Peregrine Falcons, and Brown Pelicans.

Decline in Hatching Rates:
Due to the thinning of eggshells, the hatching rates of birds that have been exposed to DDT decline significantly. This means that fewer chicks are born, leading to a decline in the overall population of the bird species.

Conclusion:
The decline in the population of birds due to DDT is a significant environmental issue. It is essential to limit the use of DDT and other persistent organic pollutants to protect the health and well-being of the ecosystem. The ban on DDT in most countries has helped to restore the populations of several bird species, but the effects of DDT are still felt in some areas where it was used extensively in the past.

Non-point sources of water pollution refer to sources that are diffuse and difficult to pinpoint to a specific location. Let's understand this in detail.

Definition of Non-Point Sources of Water Pollution

Non-point sources of water pollution refer to pollution that comes from various sources and is not discharged from a specific location, such as a factory or sewage treatment plant. Examples of non-point sources of pollution include agricultural runoff, stormwater runoff, and residential runoff.

Characteristics of Non-Point Sources of Water Pollution

The characteristics of non-point sources of water pollution are as follows:

- Diffuse: Non-point sources of pollution come from various sources, making it difficult to pinpoint the exact location of the pollution.
- Episodic: Non-point sources of pollution occur at different times and are not constant.
- Difficult to monitor: Non-point sources of pollution are difficult to monitor as they are not discharged from a specific location.

Examples of Non-Point Sources of Water Pollution

Some examples of non-point sources of water pollution are:

- Agricultural runoff: Pesticides and fertilizers used in agriculture can wash into nearby water bodies, causing water pollution.
- Stormwater runoff: When it rains, water runs off surfaces such as roads, parking lots, and rooftops, picking up pollutants such as oil, grease, and metals before entering the water system.
- Residential runoff: Residential areas can contribute to water pollution through activities such as lawn care, car washing, and improper disposal of household chemicals.

Conclusion

Non-point sources of water pollution are a significant environmental concern as they can have a cumulative impact on water quality. It is essential to understand the characteristics and sources of non-point sources of pollution to implement effective pollution control measures.

Explanation:

The correct sequence of continents in decreasing order of their yearly carbon dioxide emissions at present is as follows:

B. Asia
Asia is the continent with the highest carbon dioxide emissions, accounting for approximately 50% of the world's total emissions. The main sources of emissions in Asia are energy production, transportation, and industry.

D. North America
North America is the second-largest emitter of carbon dioxide, accounting for approximately 20% of the world's total emissions. The United States and Canada are the main sources of emissions in North America, with the energy and transportation sectors being the largest contributors.

C. Europe
Europe is the third-largest emitter of carbon dioxide, accounting for approximately 10% of the world's total emissions. The main sources of emissions in Europe are energy production, transportation, and industry.

A. Africa
Africa is the continent with the lowest carbon dioxide emissions, accounting for approximately 4% of the world's total emissions. The main sources of emissions in Africa are energy production and transportation.

Therefore, the correct answer is option B: B, D, C, A.

Residential Areas Noise Standards in India

Introduction: Noise pollution is a major problem in Indian cities, especially in residential areas. It can lead to several health issues such as hearing loss, sleep disturbance, hypertension, and stress. In order to control noise pollution, the Central Pollution Control Board (CPCB) has prescribed noise standards for different areas, including residential areas.

Day Time Noise Standards: The day time noise standard prescribed for residential areas in India is 55 dB. This means that the noise level during the day should not exceed 55 decibels.

Night Time Noise Standards: The night time noise standard for residential areas is lower than the day time standard. It is set at 45 dB. This is because people need a peaceful environment to sleep at night.

Impact of Noise Pollution on Health: Noise pollution can have several negative impacts on health. Some of the most common health problems caused by noise pollution include:

- Hearing Loss
- Hypertension
- Stress
- Sleep Disturbance
- Cardiovascular Diseases

Measures to Control Noise Pollution: There are several measures that can be taken to control noise pollution in residential areas. Some of these measures include:

- Use of Noise Barriers: Noise barriers can be installed along busy roads to reduce the amount of noise that enters residential areas.

- Planting Trees: Trees can help reduce noise levels by absorbing sound waves.

- Regulation of Traffic: Traffic regulation can help reduce noise pollution in residential areas. This can be done by imposing speed limits, restricting the use of horns, and enforcing noise emission standards for vehicles.

- Use of Low-Noise Equipment: The use of low-noise equipment such as lawn mowers, generators, and construction equipment can help reduce noise pollution in residential areas.

Conclusion: Noise pollution is a major problem in Indian cities, especially in residential areas. The day time noise standard prescribed for residential areas in India is 55 dB. In order to control noise pollution, it is important to take measures such as using noise barriers, planting trees, regulating traffic, and using low-noise equipment.

Explanation:
Smog is a type of air pollution that can have harmful effects on human health and the environment. It is a mixture of fog and smoke, sometimes with added pollutants such as ozone.

What is smog composed of?
Smog is composed of various pollutants, including nitrogen oxides, sulfur oxides, ozone, and particulate matter. These pollutants are released by sources such as vehicle emissions, industrial processes, and the burning of fossil fuels.

Types of smog:
There are two types of smog, namely, classical smog and photochemical smog. Classical smog is caused by the burning of fossil fuels and is common in cities with a lot of traffic, while photochemical smog is caused by the reaction of sunlight with pollutants such as nitrogen oxides and volatile organic compounds.

Effects of smog:
Smog can have a number of harmful effects on human health, including respiratory problems such as asthma and bronchitis. It can also irritate the eyes, nose, and throat, and can even cause headaches, dizziness, and nausea. In addition to its effects on human health, smog can also have a number of negative environmental effects, including acid rain, damage to crops and forests, and harm to wildlife.

Prevention of smog:
To prevent smog, it is important to reduce the amount of pollutants released into the air. This can be done by using cleaner forms of energy, such as wind and solar power, and by reducing the use of fossil fuels. It is also important to reduce vehicle emissions by using public transportation, carpooling, or walking or biking instead of driving alone.

Conclusion:
In conclusion, smog is a type of air pollution that is composed of fog and smoke, sometimes with added pollutants such as ozone. It can have harmful effects on human health and the environment, and it is important to take steps to reduce its impact by reducing the amount of pollutants released into the air.

Water Pollution: Explanation and Examples

Introduction:
Water pollution refers to the contamination of water bodies like lakes, rivers, oceans, groundwater, and aquifers. It occurs when pollutants are discharged into water bodies without adequate treatment or when natural processes are unable to remove them.

Examples of Water Pollutants:
There are various types of water pollutants, such as chemicals, microorganisms, plastics, and sediments. Some of the common examples of water pollutants are as follows:

- Chromium: It is a heavy metal that is used in industrial processes like electroplating, tanning, and dyeing. Chromium can cause skin irritation, respiratory problems, and cancer.
- Silt: It is a type of sediment that is generated due to soil erosion caused by deforestation, construction activities, and agricultural practices. Silt can clog the waterways and reduce the oxygen levels, which can harm aquatic life.
- Glacier: It is not a water pollutant, but a natural feature formed by snow accumulation over several years. Glaciers are a source of freshwater, and their melting can contribute to the rise in sea levels.
- Arsenic: It is a toxic element that is found naturally in some groundwater sources. Arsenic can cause skin lesions, cancer, and other health problems.

Conclusion:
In conclusion, water pollution is a serious environmental problem that can have severe consequences for human health and the ecosystem. It is important to take measures to reduce water pollution by implementing proper waste management practices, using eco-friendly products, and promoting sustainable development.