Answer:
Growing and selling opium.
Step-by-step explanation:
The Taliban agreed to cooperate with the UN in order to reduce the opium production of Afghanistan since 2000. Opium was declared un-Islamic, and production reduced by 99% (in terms of area of opium poppy farming in Taliban-controlled areas). However, the reduction in production benefitted a small group of drug lords. Therefore, due to market manipulation, some government leaders were able to make significant amounts of money thanks to opium production.