Hong Kong's Acting Secretary for the Environment Kitty Poon Wednesday said the government is studying the feasibility of forming pilot low-emission zones targeting franchised buses.

Poon told legislators that franchised buses account for a high proportion of vehicular flow on busy corridors in Causeway Bay, Central and Mong Kok.

"For instance, franchised buses could account for up to 40 percent of the vehicular flow along Yee Wo Street, Causeway Bay. As such, pilot studies on franchised buses can effectively test whether low-emission zones can significantly improve roadside air quality," she said.

"The implementation of the pilot low emission zones may be delayed if the pilot scheme covers all vehicles at the same time, as we will need to resolve complicated legal and traffic management issues, and consult the transport trades."

Poon said the crucial factor lies in whether franchised bus companies can provide and deploy sufficient environment-friendly buses to run in the low-emission zones.