One in every seven working Yemeni is employed in producing and distributing qat, making it the largest single source of rural income and the second largest source of employment in the country after the agriculture and herding sector, exceeding even the public sector, according to the World Bank.
Many of Yemen's poorest families admit to spending over half their earnings on the leaf.
"Qat is the biggest market in Yemen, bigger than oil, bigger than anything," said Abdulrahman Al-Iryani, Yemen's former water minister and founder of 'qat uprooting', a charity which supports farmers in replacing qat shrubs with coffee plants.