Delhi government and Japan's Fukuoka Prefecture on Tuesday signed a cooperation agreement in various sectors including environment and air pollution.A mutual treaty, which was earlier signed in 2007 and then in 2012 in several sectors was extended during a Memorandum of Understanding (MoU) signing ceremony here with environment and pollution as the key avenues.Delhi Chief Minister Arvind Kejriwal said the MoU will take forward the friendship between Fukuoka Prefectural Government (FPG) and the Government of the National Capital Territory of Delhi (GNCTD)."We hope to harness our further potentials in the spheres of environment and air pollution, being a major issue of concern with us today," Kejriwal said during the ceremony.In the proposed agreement, other areas of cooperation that have been mutually emphasised are -- culture, tourism and heritage, education and youth exchange.The Chief Minister said that inception of Delhi Metro was an example of the "fruitful" partnership.We hope to expand this cooperation in other modes of transport and their multi-modal integration," he added.