Children learn about Earth at Changxing Jindingzi Geological Museum in Huzhou, East China's Zhejiang province, on April 21, 2021. (WU ZHENG / ASIANEWSPHOTO)

Every year on April 22, Earth Day marks the anniversary of the birth of the modern environmental movement in 1970. 

It highlights environmental issues, including the loss of biodiversity and increasing pollution. 

The theme for this year's observance is "Restore Our Earth".

Students paint a "green Earth" on a soccer ball at an event on protecting the environment and Earth at Heping Primary School in Yaohai district of Hefei, East China's Anhui province, on April 19, 2021. (XIE CHEN / ASIANEWSPHOTO)

Students hold up a cloth which they painted their imaginary homes on at an event on protecting the environment and Earth at a community in Luyang district of Hefei, East China's Anhui province, on April 19, 2021. (ZHAO MING / ASIANEWSPHOTO)

Students listen as a teacher talks about Earth while holding a globe at Fuhe Primary School in Hanshan district of Handan, North China's Hebei province, on April 21, 2021. (HAO QUNYING / ASIANEWSPHOTO)

People sign their names on a banner at an event on protecting the Earth in Luyang district of Hefei, East China's Anhui province, on April 21, 2021. (GE CHUANHONG / ASIANEWSPHOTO)

Children in costumes made from plastic bags and other materials walk at a show during an event on environmental consciousness in Changxing county, Huzhou, East China's Zhejiang province, on April 21, 2021. (WU ZHENG / ASIANEWSPHOTO)

Workers clean a river in Taizhou, East China's Zhejiang province, on April 19, 2021. (JIANG YOUQING / ASIANEWSPHOTO)