By Edgar Gutierrez - President of the UN Environment Assembly, Minister of Environment and Energy of Costa Rica

The United Nations Environment Assembly has been called the“Parliament of the Environment.” The highest level of authority on the environment in the United Nations system, it is a unique and inclusive body that brings together high-level decision makers, civil society, experts, business represent

By Judi Wakhungu - Cabinet Secretary, Ministry of Environment and Natural Resources, Kenya

Kenya faces major challenges in waste management. Most urban centres lack basic waste management structures and open dumping is the most popular option. A close look at problematic waste at roadsides, rivers, dumpsites, and most public spaces revealed that polythene bags were most widespread.

By Michael Gove - Secretary of State for Environment, Food and Rural Affairs, United Kingdom

Few will forget the day in April 2010 a BP oil rig exploded in the Gulf of Mexico. Oil gushed for 87 days and the world reacted with horror. Birds, fish and marine mammals lay lifeless along the coastline, consumed by the deadly waste.

By Corine Mauch - Mayor of Zurich, Switzerland

Humankind's future will largely be decided in cities. Half the world's population already lives in them, and by 2050 this will have risen to 70 per cent.

By Mario Molina - Nobel Prize Laureate in Chemistry

Ozone depletion was the first human threat to the global atmosphere to be recognized. It was also the first to be addressed by the international community. The results have been truly remarkable.

By Virginie Helias - Vice President of Global Sustainability, Procter & Gamble

The consumer goods industry has entered an era of responsibility, where companies, consumers, governments and non-governmental organizations are collaborating more and more frequently to address some of the biggest challenges facing the world.

By Matt Damon - Actor, Film Producer, Screenwriter and Co-founder,

There are women we work with who wait for hours to answer the call of nature. They can "go" on the edge of their village, on the river, or on the train tracks. Open defecation leads to all kinds of problems.

By Ellen MacArthur - Founder and Chair of Trustees, Ellen MacArthur Foundation

Over 8 million tons of plastic pollute the oceans each year. The problem is so severe that, if nothing changes, there could be more plastic than fish in the sea by 2050. We must urgently rethink how we make and use this ubiquitous material, now a staple of our modern economy.

By Olga Speranskaya - Co-Chair, International POPs-Elimination Network

Toxic chemicals threaten current and future generations. To protect them, we must change course by shifting our chemical practices to a more sustainable model.

By Lucia Buvé - Pollution Prevention Manager, Umicore, Brussels, and Chair of the Network for Industrially Co-ordinated Land Management in Europe

Over hundreds of years, industrial activities including mining, chemical production, manufacturing of consumer goods and agriculture introduced pollutants into the soil, contaminating it along with groundwater, often over large areas.