To have a ~ on something means to have control over it and prevent it from being free or from developing.
These companies are determined to keep a ~ on the banana industry...
N-SING
To have a ~ on something means to have control over it and prevent it from being free or from developing.
These companies are determined to keep a ~ on the banana industry...
N-SING
Collins COBUILD. Толковый словарь английского языка для изучающих язык Коллинз COBUILD (международная база данных языков Бирмингемского университета) . 2012