  We compare the photon emission rates from hot hadronic matter with in-medium
mass shift and Quark Gluon Plasma (QGP). It is observed that the WA98 data can
be well reproduced by hadronic initial state with initial temperature $\sim
200$ MeV if the universal scaling of temperature dependent hadronic masses are
assumed and the evolution of temperature with time is taken from transport
model or (3+1) dimensional hydrodynamics. The data can also be reproduced by
QGP initial state with similar initial temperature and non-zero initial radial
velocity.
