Dear Shrivastava,
It is not fair on employers part to cheat employees and vice versa. SUNDAY is a GOVERNMENT HOLIDAY and it cannot be considered as LOP. You may define your policies based on NEED just to maintain DISCIPLINARY STANDARDS by not allowing your employees to avail leave(continuous) without valid reason and systematic job handover.
If its really needed, on emergency ground and based on genuine reason(s), you may allow your employees to take off along with Sunday without counting as LOP.
With profound regards