In May 2022 the Indian government responded to a heatwave that had cut crop yields by unexpectedly banning wheat exports. Ministers spoke of the need for domestic food security, and the important of reducing wheat prices for the India’s citizens. But the policy was unpopular with domestic farmers and in countries that imported wheat, where prices had already risen following the Russian invasion of Ukraine. Allan Hsiao talks to Tim Phillips about how common these policy interventions really are – and the consequences for governments and trade, consumers and farmers.