A burner assembly (100) for flaring low calorific gases, such as methane with high carbon dioxide content, may be configured to provide a gradual decrease in flow velocity. The burner assembly (100) may include a conical deflector (140) that creates a relatively large recirculation zone (154) downstream of the deflector (140), thereby to stabilize fluid flow. A swirl inducing structure positioned in a final stage of the burner assembly (100) further stabilizes the fluid flow and flame at different gas flow rates.