  Effect of shear viscosity on elliptic flow is studied in causal dissipative
hydrodynamics in 2+1 dimensions. Elliptic flow is reduced in viscous dynamics.
Causal evolution of minimally viscous fluid ($\eta/s$=0.08), can explain the
PHENIX data on elliptic flow in 16-23% Au+Au collisions up to $p_T\approx$3.6
GeV. In contrast, ideal hydrodynamics, can explain the same data only up to
$p_T\approx$1.5 GeV. $p_T$ spectra of identified particles are also better
explained in minimally viscous fluid than in ideal dynamics. However,
saturation of elliptic flow at large $p_T$ is not reproduced.
