As we described in the previous chapter, regional integration in the PYSR has been primarily driven by business sectors taking advantage of economic complementarities across borders, combined with the favourable waves of decentralisation and globalisation since the 1990s. Following this economic integration, many other sectors in the PYSR have also built extensive interregional networks. One notable case is the transportation network. Having benefited from their world-class port facilities, many cities in the PYSR have actively constructed dense port linkages to be the backbone of regional integration. Another example is the socio-cultural network, inspired by historic ties and intensified further by the increasing movement of people and goods across borders. Especially among the younger generation in the PYSR , cultural exchanges are sharply growing. The environmental co-operation network has also had substantial outcomes. Many dialogue channels are being created and several projects to address common environmental concerns in the PYSR have been launched. Against this background and a conceptual framework developed in Section 1.4, in this chapter we first analyse the PYSR ’s production network (Section 2.1), then move on to the transportation network (Section 2.2) and the socio-cultural network (Section 2.3). Finally in Section 2.4 we discuss environmental co-operation.