Developing countries face several barriers to trade within regional blocks, including poor physical infrastructure like lack of railway connections, arduous customs processes, and differing policies on skilled labor. They also highly depend on exports to advanced nations for imports and markets, but these export markets can be unstable since they rely on primary commodities. Landlocked countries further depend on neighbors' infrastructure, relations, stability, and practices. Developing countries also face limited market access due to protectionism and trade barriers from advanced nations, especially in agriculture where subsidized surpluses are dumped on world markets at lower prices.