Determine weekend based on country
Try to test the following: 

select
TO_CHAR (issue_date, 'D', 'NLS_DATE_LANGUAGE=HINDI) IN (6, 7)
from table 


To see if it works for you. One thing you need to check is, depending on the country, if the week starts at a Monday or Sunday. You might have to change those in values accordingly.
Edit: doing this, you're only changing the value on the query. Isn't it what you wanted? And sorry for not getting the value right. Corrected.