BEIJING, June 5 (Xinhua) -- Chinese President Xi Jinping has sent a congratulatory letter to the World Environment Day celebrations Wednesday in Hangzhou city, Zhejiang Province, calling for joint efforts to promote green, low-carbon and sustainable development.

"We only have one Earth. Protecting ecological environment and pushing sustainable development are our joint obligations," Xi said in the letter.

While the international community is actively pushing for the implementation of the UN 2030 Agenda for Sustainable Development, countries are facing severe challenges including environmental pollution, climate change and declining biodiversity, Xi noted.

He stressed that China has attached great importance to environment protection, acted on the understanding that lucid waters and lush mountains are invaluable assets, and sought harmony between human and nature.

Remarkable progress has been made as China included the building of an ecological civilization in the country's overall development plan, Xi said, adding China is willing to work with other countries on the path of green growth and make positive contributions to the building of a community with a shared future for mankind.

China is the global host of the 2019 World Environment Day celebrations, and the main event is being held in Hangzhou in east China.