Agenda-21 was adopted in

Options

A. Kyoto protocol
B. Earth summit
C. Helsinki declaration
D. Montreal protocol

Answer

To answer the question "When was Agenda 21 adopted?", we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Context**: Understand what Agenda 21 is. It is a comprehensive plan of action to be taken globally, nationally, and locally by organizations of the United Nations System, Governments, and Major Groups in every area in which human impacts on the environment.

2. **Locate the Event**: Agenda 21 was adopted during a significant international conference. This conference is known as the United Nations Conference on Environment and Development (UNCED).

3. **Specify the Location**: The conference where Agenda 21 was adopted took place in Rio de Janeiro, Brazil.

4. **Determine the Dates**: The conference occurred from June 3 to June 14 in the year 1992.

5. **Conclude the Answer**: Therefore, Agenda 21 was adopted on June 14, 1992, during the Earth Summit in Rio de Janeiro.

### Final Answer:
Agenda 21 was adopted on June 14, 1992, during the Earth Summit in Rio de Janeiro.

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