In this age of technological advancement, you need to update yourself. Indian BPO industry is ever growing and expanding. To attract youngsters into this field, BPO industries are working hard for providing lucrative career opportunities and a youngster-centric work culture.
This has led to the introduction of in built coffee houses and canteens for employers, accommodation facilities and even condom vending machines for those working in night shifts(Although now it has been closed after strong protest from certain political and social organizations).
Weekend parties are often organized regularly by some BPOs to keep these employers working in the same industry as the switching rate is very high in BPO industry.
Although they provide lot of facilities, pay and perks to their employer, they do not force it upon you. Its up to you to avail any service or offer. They would be more than happy if you choose to abstain from all these activities as it save them some cost.
And a far as your vegetarian credentials are concerned, you are safe in a BPO industry. They don't serve beef, porn or liquor in canteens. They do have some work ethics. All you can find in their canteens is general snacks that can be eaten by a vegetarian.
In most of the BPOs, there is no dress code, they just ask you to dress "decently" and nothing else. You can choose to be large beard or clean shaven, it doesn't matter as the client is never going to see you in personal.
A pleasing voice, good English and a convincing personality is all that needs to be a success in BPO industry. Rest depends on your hard work and luck.
I hope you got the answer.