Why were pops singled out for regulation by the international community?

According to the European Commission, the POP (Persistent Organic Pollutant) are chemicals that should be eliminated. The international community called for an action to reduce and eliminate POP. To arrive at this solution having two agreements. First is The Protocol to the regional UNECE Convention on Long-Range Transboundary Air Pollution (CLRTAP) on POPs called for open signatures in June 1998 and entered into force on 23 October 2003. Second is The global Stockholm Convention on POPs, opened for signatures in May 2001 and entered into force on 17 May 2004

 The correct answer is :  Because persistent organic pollutants are chemical substances that persist in the environment, they do not decompose easily and can travel long distances. They represent a risk to the environment and to human health. They are formed by pesticides, by industrial chemicals and byproducts of industrial processes.

The answer is B: Destroy ships and planes that threatened their expansion efforts.

I hope this helps! I wish I could give an explanation, but I gotta get to class! Have an amazing day!