Mechanics found that the vehicle’s parts were all operating normally upon inspection, according to a New World First Bus and Citybus spokesperson. The air-conditioning units have been adjusted, and the bus will resume service today.

The company will continue to collect operational data on electric double-decker buses for maintenance purposes, the spokesperson added.

Traffic information forum hkitalk.net reported that passengers experienced great discomfort when the air-conditioning on the bus broke down, and netizens also left messages on the Faceboook page regarding the incident.

“It’s like the old ‘hot dog buses’ (non-air-conditioned buses)!” one netizen joked. “Hong Kong’s first sauna bus,” said another.

The double-decker first came into service on Sunday. Citybus has pledged to operate a full fleet of zero-emission buses across operations by 2045, which is five years ahead of the government's carbon neutrality target.