Why was the Montreal Protocol signed

Explanation

**Step-by-Step Text Solution:**

1. **Understanding the Context**: The Montreal Protocol is an international treaty that was established to address environmental concerns, specifically the depletion of the ozone layer.

2. **Year of Signing**: The protocol was signed in 1987. This is an important detail as it marks the beginning of international efforts to combat ozone depletion.

3. **Full Name of the Protocol**: The complete name of the protocol is "Montreal Protocol on Substances that Deplete the Ozone Layer." This name indicates its specific focus on substances harmful to the ozone layer.

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