"To deal with plastic pollution, humanity must change," says Kenyan President William Ruto as he opens the latest negotiations towards a global treaty to combat plastic pollution, in Nairobi. Some 175 countries agreed last year to conclude by 2024 a UN treaty to address the plastic blighting oceans, floating in the atmosphere, and infiltrating the bodies of people and animals.  While there is broad consensus a treaty is needed, there are very different opinions about what should be in it. IMAGES AND SOUNDBITES