6. Dangerous and unfair bowling
(a) Bowling of fast short pitched balls
(i) The bowling of fast short pitched balls is dangerous and unfair if the umpire at the bowler's end considers that by their repetition and taking into account their length, height and direction they are likely to inflict physical injury on the striker, irrespective of the protective equipment he may be wearing. The relative skill of the striker shall be taken into consideration.
(ii) Any delivery which, after pitching, passes or would have passed over head height of the striker standing upright at the crease, although not threatening physical injury, shall be included with bowling under (i) both when the umpire is considering whether the bowling of fast short pitched balls has become dangerous and unfair and after he has so decided. The umpire shall call and signal No ball for each such delivery.
(b) Bowling of high full pitched balls
(i) Any delivery, other than a slow paced one, which passes or would have passed on the full above waist height of the striker standing upright at the crease is to be deemed dangerous and unfair, whether or not it is likely to inflict physical injury on the striker.
(ii) A slow delivery which passes or would have passed on the full above shoulder height of the striker standing upright at the crease is to be deemed dangerous and unfair, whether or not it is likely to inflict physical injury on the striker.