He Liwen made over 500 phone calls on March 27, directing dozens of trucks to transport concrete from mixing plants in Shenzhen to the construction site of the Central Government-Aided Emergency Hospital in Lok Ma Chau in the Hong Kong Special Administrative Region.

When the 33-year-old manager ended the last call, it was 3 am. In front of him, searchlights illuminated the unfinished hospital where builders were still working and machines were humming.

He is among the thousands of Chinese mainland workers who crossed the border in early March to build the hospital. With their help, the hospital's first phase was completed on April 5 as scheduled, providing 500 negative-pressure isolation wards for treating COVID-19 patients.

Hong Kong Chief Executive Carrie Lam Cheng Yuet-ngor thanked the central government on Saturday for its assistance in building the emergency hospital, saying it is crucial to augmenting the city's capacity to treat COVID-19 patients.

Lam said the SAR's fifth outbreak had raised the government's awareness about the importance of medical resources. Existing community quarantine facilities will continue to operate after the outbreak ends, Lam said.

The emergency hospital is one of a number of central authorities' efforts to help Hong Kong battle its worst COVID-19 outbreak.

The project, which is being built in two phases, includes an emergency hospital, a community treatment facility and living facilities for staff members and patients. It covers 50 hectares in the eastern part of Lok Ma Chau Loop, where land in the western part is earmarked for a technology park.

An engineering department manager for the China Construction Science and Industry Corp, He was assigned to lead a six-member team in charge of procuring and transporting construction materials for the project, including concrete, steel, equipment and tents.

In late March, Shenzhen shut down some concrete-mixing plants under pandemic-control measures, causing an unexpected concrete shortage for the project.

He devised a timetable to coordinate pouring concrete in 16 site locations and called the plants to mix concrete according to his schedule. At the same time, He contacted construction supervisors and asked them to give access to concrete trucks to enter, unload and return to the mixing plants at the fastest speed.

He made over 500 calls that day, ensuring the construction plan was completed successfully. Such a busy project also brings greater safety risks.

Xu Jiachen, 28, from China Construction Shenzhen Decoration Co, is in charge of on-site construction safety management. Xu and his seven colleagues patrol the construction site in shifts 24 hours a day to detect potential safety hazards caused by improper manual operation or mechanical failure.

On their rounds, they have to check each area carefully and supervise workers to follow safety guidelines. "It usually takes four to five hours to finish the 8-kilometer patrol," Xu said.

When the project is completed, the hospital will have 1,000 beds. The second phase of construction is expected to be completed by the end of this month.