  Ratio of the yield of strange hadrons to pions is considered as an important
observable in studying the properties of the system produced in relativistic
heavy ion collisions. Production of strange hadrons $K, \bar{K}, \Lambda,
\Sigma, \Xi$ and $\Omega$ have been evaluated microscopically using rate
equations by considering their hadronic interaction cross sections in an
expanding medium. The yields obtained from rate equations are normalized with
thermal pions and compared with the measurements from Pb-Pb collisions at
various multiplicities at LHC energy. The calculation has been done for various
initial and freeze out conditions. At 2760 GeV, LHC energy, $\Lambda, \Xi,
\Omega$ freeze out close to $T_C$ and $K^0_s$ freezes out little later. But
there is a subtle difference in freeze out temperatures of different species
which may be distinguishable at lower colliding energies.
