This Economic Corridor 1 (EC1) hosts some of the most agriculture-rich provinces in Southern Thailand that trade with Malaysia, Sumatra, and Singapore; and plays an important role in the supply chain of traded goods outside the subregion. The corridor covers the well-established international gateways of Songkhla, Penang, and Medan with well-equipped seaports that are important for bulk shipment of goods within the subregion and for providing onward shipping services to East Asia and Europe. The Songkhla to Penang subcorridor is a very important corridor for Thai exporters, particularly of rubber and related products, as well as agro-based products. However, customs facilities in this subcorridor need to be expanded to avoid delays due to congestion, especially during peak hours. The Medan–Penang subcorridor is well-developed although there is a need to improve inter-modal connection, including RoRo services, for greater efficiency and improved access to Belawan Port. Nakhon Si Thammarat 2 ADB. 2009. Mid-Term Review: Transport and Infrastructure Sector Strategy. Province has vast potential for developing economic linkages with the rest of IMT-GT. The Hua It Agricultural Wholesale Market, located in the province, is the largest wholesale market in Southern Thailand supplying agricultural products to Malaysia and Singapore. Phatthalung Province, located in the rice-growing plain of Southern Thailand, also offers huge potential for cattle-raising to supply the IMT-GT subregion with meat and dairy products.