Environmental Issues Class 12 Notes

According to the CBSE Syllabus 2023-24, this chapter has been removed from NCERT Class 12 Biology textbook.

With the increase in the human population, there is a lot of demand for food, clothing, housing, fuel, vehicles etc. All these demands are exerting a lot of pressure on land, water, air and other natural resources, which leads to pollution, environmental degradation, biodiversity, and other environmental issues.

Let us have a look at the different environmental issues and their solutions in detail.

What Are Environmental Issues?

An environmental issue can be defined as the harmful effects of any human activity on the environment. This leads to the degradation of air, water and soil quality. These unfavourable changes often lead to environmental issues that affect the natural balance of the environment.

Environmental Issues

Types of Environmental Issues

Listed below are the major causes of environmental issues.


Pollution is generally defined as an undesirable change in the biological, chemical and physical composition of air, water, and soil. The agents responsible for the cause of pollution are called pollutants. Different types of pollution include,

  • Air pollution
  • Water pollution
  • Noise pollution
  • Soil Pollution
  • Radioactive Pollution

 Global Warming

Global Warming refers to the gradual increase in the average temperature of the Earth’s atmosphere. This happens due to an increase in the levels of greenhouse gases in the atmosphere that prevent the heat from escaping into outer space, thereby making the earth warm. It is a serious environmental issue which is caused by both natural and human influences.

The main causes of global warming include,

  • Deforestation
  • Industrialization
  • Emissions from vehicles
  • Factory farming

Solid Waste

Solid waste includes waste from homes, offices, schools and hospitals that are collected and disposed of by the municipality. These generally comprise paper, plastics, metals, rubber, glass, textile, leather, etc. The waste is either burnt or dumped in sanitary landfills.

Depletion of Natural Resources

It is a crucial current environmental problem caused by the consumption of fossil fuels that result in the emission of greenhouse gases, which is mainly responsible for global warming and climate change.


This is another environmental issue that is the result of the destruction of forests for construction and raw materials. This has added to a number of environmental problems, such as soil erosion, global warming, extinction of biodiversity, etc.

Environmental Issues Solutions

The following are the solutions to environmental issues.

  • Recycling of waste
  • Conservation of water and electricity
  • Use reusable items instead of disposable items
  • Avoid using plastics
  • Minimise the use of vehicles

Other causes of environmental issues include loss of biodiversity, deforestation, ozone layer depletion, public health issues, effect on marine life, increased carbon footprint, etc.

To learn more about Environmental Issues, keep visiting BYJU’S website.

Few Important Questions

Define Eutrophication.

Eutrophication refers to the enrichment of the water body with nutrients and minerals, which results in excessive algal growth. This results in the depletion of oxygen in the water body.

What is biological magnification?

Biological magnification or biomagnification refers to the accumulation of toxins, such as pesticides, in the tissues of tolerant organisms at very high levels in the food chain.

List out the causes of global warming.

Global warming is mainly caused due to increased levels of greenhouse gases in the atmosphere that is the result of deforestation, emission from vehicles, industrial smoke, etc. The increased levels of greenhouse gases form a layer in the atmosphere and prevent the heat from escaping into outer space, thereby making the Earth warm.

What are the effective measures taken to reduce environmental pollution?

The measures taken to reduce environmental pollution include,

  1. Plant more trees
  2. Reduce the use of automobiles
  3. Conserve energy
  4. Use renewable sources of energy
  5. Reuse and recycle waste products
  6. Disposal of toxic waste properly

For more information on Environmental Issues, watch the below videos

Further Reading:

Environmental Issues

Global Warming

Greenhouse Effect

Frequently Asked Questions on CBSE Class 12 Biology Notes Chapter 16 Environmental Issues


What are the different types of environmental pollution?

1. Air pollution 2. Water pollution 3. Noise pollution 4. Soil pollution 5. Radioactive pollution


What is the greenhouse effect?

The overall warming of the Earth’s surface and troposphere is caused by the presence of water vapour, carbon dioxide, methane and certain other gases. This heating effect is known as the greenhouse effect.


What is the meaning of factory farming?

It is a system of rearing livestock using highly intensive methods, and this increases the risk of pathogens like E. coli and salmonella that cause food-borne illnesses in people.


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