With regard to leave entitlement please follow what ACT says.
As for as sick leaves are concerned, please find out whether they are genuine or fake. For any leave beyond 3 and above you can ask for medical proof and insist for lab results if availed. If the reason for leave is genuine (sickness) you need to accommodate.
In general for repeated leaves you can counsel them, how their absence had impact of performance of the team etc.
9th September 2019 From India, Madras
(1) Privilege Sickness or Casual.
Every employee who has become entitled to privilege leave under sub-section 1 (a) of section 22 may apply in writing to the employer indicating in advance the date from and the period for which he would like to avail of this leave during the ensuing twelve months, and no such leave would ordinarily be refused by the employer except for valid cause. In all other cases, the employee shall apply in writing ordinarily 15 days in advance and the employer shall pass his orders thereon not later than 7 days from the receipt of the application.
Provided further that no such application would be refused by the employer as would deprive the employee of his right to carry over the accumulated privilege leave.
(2) Casual & Sick leave.
(a) (i) Ordinarily, the previous permission of the employer for casual leave shall be obtained by the employee, but when this is not possible, the employer shall be informed in writing as soon as practicable for the grant of such leave. The employer shall record his order on all such applications and shall retain them till the 31st March of the following year.
(ii) An employer, however, may refuse an application for casual leave from an employee on grounds of exceptional pressure of work requiring his attendance on the day or days in respect of which casual leave has been asked for:
Provided that leave shall not be refused where it has been asked for on account of an accident, causing physical injury to the employee, death in the family or sickness of the employee, his wife or child.
(iii) Where an application for casual leave is refused by the employer under clause (ii) above, the employer shall record his reasons for refusal on the application, and shall grant equivalent leave on demand by the employee in the same calendar year.
(b) (i) No application from an employee for sickness leave shall be refused, but if in any case, the employer is not satisfied about the correctness of the assertion set out therein, the employer may either (i) require the employee to submit medical certificate in respect thereof from a registered medical practitioner, or (ii) get the employee or the wife or the child of the employee, as the case may be, examined at his (employer's) own expense by a registered medical practitioner (lady doctor in case of females) for the purpose of verifying the facts mentioned in the leave application and may grant or reject the application on the basis of the certificate of such medical practitioner.
(ii) Every such medical certificate shall be retained by the employer till 31st March of the following year.
9th September 2019 From India, Delhi