the penalty for wilful insubordination unaccopmpanied by any major financial loss cannot be dismissal more so for an employee wth no blemished record of the past. If it is too simple instance of wilful insubordination and if it is the first instance, you may award a penalty of warning since he is a contributing memeber and served the company for a decade. If he disobyed an important instruction/order of the superiors that has bearing on the company's working, general discipline or image, you can impose a stricter penalty like stoppage of increment or increments . However what shall be the duration for which his future increment/s can be stopped and whether it should be with cumulative effect and without cumulative effect depends up on the facts and circumstances of each case.
B.Saikumar
HR & Labour law advisor
Mumbai