If the managers are very lenient with the employees which may affect the work badly, what is the thing that the supervisor should do to control his team?

In an organisation every employee at every level has their own responsibilities. Only when these responsibilities are fulfilled to the agreed levels,  the entire team can complete their task/mission/objectives. At a functional level, if a manager is lenient, supervisor should call for a one to one discussion with his manager and explain the damage and wrong message that his leniency can cause for the outcome of the entire team. It also has to ab analysed if the cause of leniency is because of the employee's personal issues or his job limitations. If that is so, then they have to suitably addressed either by additional training to the employee or shift some responsibilities to another member of the team till his personal issue is resolved or if both is not possible, reallocation of tasks has to be done.

The supervisor should immediately conduct a one on one meeting with the manager and elaborate to the manager with explanations as to the effect which the organisation will get when he is extra lenient,Actually we should Inform the Manager to take action on balancing emotional level, i.e not to be very lenient and to balance the situation.be Lenient and at the same time to practice being strong.

The thing that the supervisor should do to control his team is to be flexible and conduct meetings before and after operation.

The supervisor should keep a good relation with his head for the smoothness of his project. So complaining to his higher authorities will make things worse. He should undertake the responsibilities were his higher officials are weak in.