Hi Shweta,
Leave policy can differ from company to company, so there's no point in passing judgements like this. I hope you'll take this in positive manner.
In most of the companies, employees on probation can avail CLs on pro-rated basis as per the duration of Probation time.
Futhermore, few companies have concept of following additonal leaves other than PL,CL, SL:
1) Bereavement Leave - In case of death of any immediate family member.
2) Marriage Leave - Say for a week on account of employee's marriage
3) Parental Leave - Usually 3 day leave to a new father
I hope this would help you all to understand leave management system in more length.
Regards,
Upasna