Developing countries have been trading more with each other since the 1970s, even though they used to trade less. This increase in South-South trade happened despite high protection against products they are good at making. When growth slowed down, it changed how developing countries traded. But even when rich countries started growing again, South-South trade kept increasing. Most developing countries have rules that make it harder for other developing countries to sell their products. If all countries reduce these rules, South-South trade would benefit, especially in the most protected industries.