Sorry got confused with the last post, in case of indoor catering no service tax is chargeable, indoor catering implies restaurants, cafes etc.
In case of outdoor catering, service tax is chargeable.
“outdoor caterer” means a caterer engaged in providing services in connection with catering at a place other than his own but including a place provided by way of tenancy or otherwise by the person receiving such services;
any person who supplies, either directly or indirectly, any food, edible preparations, alcoholic or non-alcoholic beverages or crockery and similar articles or accouterments for any purpose or occasion and an outdoor caterer has been defined as a caterer engaged in providing services in connection with catering at a place other than his own.
It's important to note the part where it states, at a place other than his own. Same applies to inflight catering, service tax is chargeable on the same.