NAIROBI, May 23 (Xinhua) -- The second edition of the United Nations Environment Assembly (UNEA-2) opened on Monday, with a call for concerted efforts to revitalize green economy and sustainability agenda.

Achim Steiner, Executive Director of the United Nations Environment Programme (UNEP), speaks during the opening ceremony of the second edition of the United Nations Environment Assembly (UNEA-2), in Nairobi, Kenya, on May 23, 2016. The second edition of the United Nations Environment Assembly (UNEA-2) opened on Monday, with a call for concerted efforts to revitalize green economy and sustainability agenda. (Xinhua/Pan Siwei)

Environment ministers and representatives from over 170 countries, scientists, industry executives and campaigners are attending the five day global environmental assembly.

UN chief Ban Ki-moon said in a message sent to the meeting that UNEA-2 provides a platform to promote global conversation on revitalizing the green and sustainability agenda.

"This assembly should discuss how to implement land mark agreements like sustainable development goals and Paris climate deal adopted last year," he said.

He challenged UN member states to hasten implementation of instruments that advance low-carbon and inclusive development.

Edgar Gutierrez, President of UNEA-2, who is also the environment and energy minister of Costa Rica, speaks during the opening ceremony of the second edition of the United Nations Environment Assembly (UNEA-2), in Nairobi, Kenya, on May 23, 2016. The second edition of the United Nations Environment Assembly (UNEA-2) opened on Monday, with a call for concerted efforts to revitalize green economy and sustainability agenda. (Xinhua/Pan Siwei)

Photo taken on May 23, 2016 shows the opening ceremony of the second session of the United Nations Environment Assembly (UNEA-2) in Nairobi, capital of Kenya. The second edition of the United Nations Environment Assembly (UNEA-2) opened on Monday, with a call for concerted efforts to revitalize green economy and sustainability agenda. (Xinhua/Pan Siwei)

Photo taken on May 23, 2016 shows the opening ceremony of the second session of the United Nations Environment Assembly (UNEA-2) in Nairobi, capital of Kenya. The second edition of the United Nations Environment Assembly (UNEA-2) opened on Monday, with a call for concerted efforts to revitalize green economy and sustainability agenda. (Xinhua/Li Baishun)