The United Nations declared the decade from 1990 to 2000 as the International Decade for which global cause?

Introduction / Context:
The United Nations often declares special decades to draw sustained global attention to critical issues. Understanding these thematic decades is important for exam aspirants because they appear in questions related to international organisations, environment, and disaster management. The decade from 1990 to 2000 was declared as the International Decade for Natural Disaster Reduction, emphasising the growing concern about the impact of disasters on life, property, and development.

Given Data / Assumptions:

• The question focuses on the decade 1990 to 2000.
• It asks which global cause this decade represented according to a United Nations declaration.
• The options list four different named decades involving water, health, colonialism, and natural disasters.
• We assume the question is referring to the official UN resolution that established a thematic decade for that period.

Concept / Approach:
The United Nations General Assembly designated the nineteen nineties as the International Decade for Natural Disaster Reduction. The main objective was to reduce the loss of life and property caused by natural disasters and to encourage disaster preparedness, mitigation, and international cooperation. To answer correctly, it is necessary to connect the years 1990 to 2000 with this disaster reduction initiative rather than with other later decades such as the Water for Life Decade.

Step-by-Step Solution:
Step 1: Identify the exact period mentioned in the question, which is the decade from 1990 to 2000. Step 2: Recall that during this period the United Nations focused on natural disasters and adopted a decade long programme for reduction of disaster risks. Step 3: Connect this memory with the official title International Decade for Natural Disaster Reduction. Step 4: Examine the options and locate the one that exactly matches this title. Step 5: Choose option D, International Decade for Natural Disaster Reduction, as the correct answer.

Verification / Alternative check:
Candidates can verify this information in disaster management chapters of environment and geography books, where the history of global disaster reduction efforts is often discussed. UN documentation and standard current affairs notes mention the International Decade for Natural Disaster Reduction for the years 1990 to 2000. Additionally, many competitive exam question banks repeat this fact, which makes it easy to confirm through multiple reliable references.

Why Other Options Are Wrong:
Option A, Water for Life Decade, refers to the International Decade for Action on water from 2005 to 2015, not 1990 to 2000.
Option B, Bone and Joint Decade, is linked to a different initiative related to musculoskeletal health and is not the focus of the 1990 to 2000 UN decade in question.
Option C, Second International Decade for the Eradication of Colonialism, covers a separate timeframe and theme, and therefore does not match the decade mentioned here.

Common Pitfalls:
Students often confuse various UN decades because of similar sounding phrases like decade for action, decade for reduction, or decade for eradication. Another common error is to mix up the time periods of the Water for Life Decade and the Natural Disaster Reduction Decade. To avoid this, it is helpful to remember that natural disaster reduction is associated with the early nineties, while water for life is associated with 2005 to 2015. Making a small table that summarises decade names and their exact years is a practical revision technique.

Final Answer:
The United Nations declared the decade from 1990 to 2000 as the International Decade for Natural Disaster Reduction.