坑口
The development of Tseung Kwan O New Town (TKO) has changed route 91M a lot, as Hang Hau became part of the new town in the early 1990s. 91M was no longer the only route serving Hang Hau with the advent of the Tseung Kwan O Tunnel, which brought residents numerous new routes connecting TKO with the urban area. As the population of Hang Hau district was initially expected to dwindle during the development, KMB once proposed the withdrawal of this route in 1988 and obtained permission from the Government's Transport Department. The latter responded by inviting tenders to the operation rights of a new green minibus route running almost the same route with 91M. However, plans of cancelling route 91M was ultimately shelved, and the green minibus route (present route 11) went into operation anyway. It was eventually extended to On Ning Garden inside the newly reclaimed and -developed part of Hang Hau in 1991.