Answer:
Following are the measures to control black market:
Give rewards for the people who provide information about the existence of black market.
The private sectors has to create a strict coding systems for their products in order to avoid black marketing so if some products are missing from their usual distribution route, then it will be easier for the government to track it down.
Strict training of government officers for conducting fake transaction. They officers have to send as 'Buyers' in order to crack down existing black market and catch them on the spot.