Have a look at below screenshot where they have used green colour strategically while announcing the EID Mubarak with Shahrukh Khan who is their brand ambassador in a sherwani which is a religious dress worn on special occasions.
On similar lines BSNL 786 recharge voucher was launched at the beginning of the Ramadan period to woo the population by offering them 786 mins of talk time whether local or STD. However one has to amke sure that while using such type of campaigns one does not hurt any religious feelings and if this strategy is exercised properly; one may have returns which can be multiple times than the effort and money required to launch the campaign. Last but not least you can Watch Live Tarawih Prayers here.