Optical afterglow observations of GRB 021004 and GRB 030226

We present our multi‐band optical afterglow observations of the long duration GRB 021004 and GRB 030226 in combination with other published data to study the nature of the bursts. Optical afterglow light‐curves of both the GRBs exhibit signatures of collimated outflow. Observed superimposed variability in the case of GRB 021004, in the form of bumps and wiggles, suggest density fluctuations in the ambient medium. The derived temporal and spectral flux decay indices of GRB 030226 afterglow show an inconsistency with the theoretically predicted values.