Dear Umamaheswararaji,
My view is different than others.
The long leave is called as privilege leave or leave with wages. Those leaves are granted under FA in case FA is applicable else under S&E Act.
Under FA you are entitled for one day leave for every 20 days of working. Under S&E Act 21 days leave with wages are given annually.
In case of daily rated workmen employed in factory, the 20 days of working are actual working days. In this case, intervening Sundays or weekly offs which are unpaid, are not treated as leave with pay.
In case of monthly rated employees, leaves are calculated on total days of working including Sundays / weekly off days which are paid to them. In this case, intervening Sundays / weekly off days / holidays are treated as leave with wages.