Any undesirable change in the physical, chemical or biological characteristics of air, land, water or soil is called which environmental problem?

Introduction:
Understanding basic environmental terminology is essential for general science and current affairs. This question asks for the correct term used when the physical, chemical, or biological characteristics of air, water, land, or soil change in an undesirable way. Such changes affect living organisms and natural systems and are a core topic in environmental studies.

Given Data / Assumptions:

• The change occurs in air, land, water, or soil.
• The change is undesirable and harmful for living beings and ecosystems.
• It can involve physical, chemical, or biological properties.
• The options include greenhouse effect, solid wastes, pollution, deforestation, and global warming.

Concept / Approach:
Pollution is defined as any undesirable change in the physical, chemical, or biological characteristics of the environment that harms living organisms or damages natural resources. It can take the form of air pollution, water pollution, soil pollution, or noise pollution. While greenhouse effect, deforestation, and global warming are serious environmental concerns, they are specific phenomena or causes, not the general term described in the definition given in the question.

Step-by-Step Solution:
Step 1: Read the definition carefully and note that it mentions any undesirable change in different media of the environment.Step 2: Recall standard textbook definitions that use almost the same wording for pollution.Step 3: Recognise that the term is broad and applies to changes in air, water, land, or soil.Step 4: Compare this with more specific concepts such as greenhouse effect and deforestation.Step 5: Select pollution as the umbrella term that matches the definition.

Verification / Alternative check:
In school level environmental science chapters, the first lines of the pollution topic usually define pollution exactly in this way. Separate sections then discuss air pollution, water pollution, and soil pollution. Greenhouse effect and global warming may be described as consequences or related phenomena caused partly by pollution, but they are not the same as the basic definition.

Why Other Options Are Wrong:
Greenhouse effect refers to the process by which certain gases trap heat in the atmosphere, leading to warming. Solid wastes are materials that have been discarded and can cause pollution but do not themselves represent the definition given. Deforestation is the clearing of forests, which can lead to soil erosion and climate changes but is a specific activity. Global warming is the long term rise in average global temperature, partly due to pollution, not the general change in environmental characteristics described in the question.

Common Pitfalls:
Learners sometimes confuse causes, effects, and definitions. For example, pollution can lead to global warming, and global warming is related to the greenhouse effect, but the definition in the question clearly covers changes in multiple environmental media. Focusing on the exact wording used in standard definitions helps avoid such confusion.

Final Answer:
Correct option: Pollution