Step 1: Understand global efforts to reduce plastic waste
Countries worldwide are increasingly committing to reducing plastic waste through international agreements, often focusing on measurable targets.
Step 2: Analyze each option
- Option (1): Canada has been proactive in plastic waste reduction, including a single-use plastics ban by 2030.
- Option (2): Australia has initiatives to reduce plastic waste but is less prominent in global agreements.
- Option (3): India faces significant plastic waste challenges and has made commitments, but its focus is often domestic.
- Option (4): The United Kingdom has led efforts in plastic waste reduction, including international advocacy.
Step 3: Conclusion
I lack specific information about a 2025 landmark agreement to reduce plastic waste by 50%. The United Kingdom or Canada are plausible candidates due to their leadership in this area, but a web search is needed to confirm.