Esi & pf applicability-urgent

Dear Members, In our Company we have 18 Employees. Among 18 employees, 13 employees are getting Rs.20,000/- P.M. and 5 employees are getting Rs.14,000/- per month. Our Plant is under construction phase. So far, we have registered neither ESI nor PF. My question 1. Whether ESI and PF applicable to us, in the given situation, or not? 2. What is the threshold limit to applicability of ESI and PF? 3. What is the salary threshold limit to deduct and pay ESI and PF? Thanks and Regards, Kiran Kumar V