Filipino senator Cynthia Villar (centre) participating in a hand-painting exercise with environmental advocates on the coast of Freedom Island to mark Earth Day in Las Pinas City, south of Manila, yesterday.

Earth Day is celebrated annually on April 22 to raise awareness and develop a sense of public responsibility towards environmentally sustainable practices. It aims to build a healthy, global ecosystem and maintain a viable planet for future generations.

According to the Earth Day Network, this year's theme is "Trees For The Earth". The organisation has started a campaign to plant 7.8 billion trees by 2020 in time for Earth Day's 50th anniversary.