Service tax is applicable when:
1. The person collecting the service tax should have collection from property rent of Rs 10 lakhs or more per annum. In your case the rent paid by you is Rs 19,500 p.m. i.e. Rs.2,34,000 per annum to a particular individual.Now. let us understand this in another way. Suppose you were paying property rents to different individuals , amounting to Rs 10 lakhs or more( for example, Rs.2,34,000 to five or more individuals). Even then, you were not required to pay service tax to each one of them, until unless anyone from the said five individuals was having a collection of Rs 10 lakhs or more annually.
2. Needless to mention that the person paying service tax need not be registered with the competent authorities. Of course, the one who is collecting the service tax has to be registered to deposit the same in the concerning "head".
I hope this helps you.
Ravindra