The upcoming International Horticultural Exhibition Beijing 2019, set to open on April 29 in Beijing's Yanqing district, will be a major gathering for people from all over the world and a "green" business card for modern China, a senior official for the exhibition said.

Ye Dahua, deputy director-general of the expo's coordination bureau, said major construction for the event has been completed and support facilities are already being used.

"The expo is not only a good opportunity for communication between people from different parts of the world, it also fosters dialogue between humans and nature," he said.

The expo, which will run until October, covers an area of 503 hectares. It will have four major themes－international, China, life experience and horticultural technology.

So far, around 110 countries and organizations have registered to participate－a record number of participants.

Han Lili, senior engineer of the Beijing Institute of Landscape Architecture, said an important objective of the expo is reminding people about the importance of nature, plants and ecological protection.

For years, Han has been studying roof greening, a method of improving the environment. She said the expo might help more people get acquainted with the concept.