Since the both ends of the capacitor on the right is connected at same point.

Both the plates of the capacitor are at same potential and potential difference across capacitor becomes 0

∴ V=0

And the capacitor C on the right now becomes useless and

Thus, capacitor is replaced by a short circuit.

The circuit now becomes

Which involve two equal capacitors of capacitance C connected in parallel.

Thus, the equivalent capacitance of the two capacitor in parallel combination is

C_eq=C₁+C₂

Since C₁=C₂=C

Putting the value in the above formula, we get

C_eq=C+C=2C

Therefore, equivalent capacitance of the combination is C+C=2C.

Thus, the equivalent capacitance of the combination is 2C