Employer contribution towards ESI if all the ESI entolled employees left the company

Do employers need to contribute towards ESI even if all the ESI enrolled employees left the company, that is, is there any minimum amount needs to contributed by the employer every month?

ESI (and EPF also) is contributed on the salary earned. If the employee has left and no salary is payable to him, on which amount the ESI is calculated and paid? However, if the employee has left service before the salary date and salary has accrued and is payable, then certainly, ESI and PF should be contributed but only in respect of that amount payable. For the coming months, any way, no contribution is payable.