  The Quantum Chromo Dynamical (QCD) phase diagram can be explored in the heavy
ion collision experiments. The non-monotonic behavior of the conserved number
fluctuations are believed to be a signatures of the QCD phase transition and
the Critical End Point (CEP) as a function of the collision energy. Due to the
experimental limitations the elementary constituents produced, are evanescent,
it is very difficult to measure the observables directly. So, we need
theoretical approaches to estimate the values of different observables. The
Polyakov-Nambu-Jona-Lasinio (PNJL) models of QCD is such an effective model,
which posses the benefit of having characteristics similar to the observables.
We present the number density fluctuation at RHIC energies and quantitative
estimates of its contribution of critical fluctuations in PNJL model.
