A Patent ceased due to non-payment of renewal fees may be restored by filing an application for…

Under section 60(1) of the Patents Act, 1970, where a patent has ceased for failure to pay a renewal fee, the patentee or his legal representative may apply for restoration "within eighteen months from the date on which the patent ceased to have effect".

The application is made in Form 15 with the prescribed fee. Twelve and forty-eight months are not the statutory period.