Often new yoga mats seem to have an unusual odor as well as a slightly slippery feel. These issues can usually be easily treated.
Before its first use, lay your yoga mat out flat for a day or two to dissipate the manufacturing odor. Then wash the new mat with a damp, slightly soapy sponge or washcloth. After washing, rinse off any soap and allow the mat to dry. This should remove any oils left over from the manufacturing process and assure that the mat does not feel slippery on initial use.
Over time the mat is likely to accumulate body oil and may become slippery. Periodically washing the mat will avoid (or cure) this problem.