He is not eligible for promotion during the currency of the punishment. This means that till the punishment period is over, he would not be considered for promotion. The officer should have appealed if the punishment was disproportionate comparing the degree of misconduct. He can appeal for lessening the punishment on sympathetic ground and /or merit. The appeal should be short(otherwise no one will read it….it is there in all hierarchy of the Govt. of W.B)and too the point. He will be lucky if he gets the reply otherwise I have seen that no one bothers for the lower ranks in police department. I wish him good luck.