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In recent years, it was found that the energy $E_{c.m.}$ in the centre ofmass frame of two colliding particles can be unbounded near black holes. Ifcollision occurs exactly on the horizon, $E_{c.m.}$ is formally infinite.However, in any physically reasonable situation this is impossible. We collectdifferent scenarios of such a kind and show why in every act of collision$E_{c.m.}$ is indeed finite (although it can be as large as one likes). Thefactors preventing infinite energy are diverse: the necessity of infiniteproper time, infinite tidal forces, potential barrier, etc. This prompts us toformulate a general principle according to which the limits in which $E_{c.m.}$becomes infinite are never achieved. We call this the kinematic censorship(KC). Although by itself the validity of KC is quite natural, its applicationallows one to forbid scenarios of collisions predicting infinite $E_{c.m.}$without going into details. The KC is valid even in the test particleapproximation, so explanation of why $E_{c.m.}$ cannot be infinite, does notrequire references (common in literature) to the non-linear regime,backreaction, etc. The KC remains valid not only for free moving particles butalso if particles experience the action of a finite force. For an individualparticle, we consider a light-like continuous limit of a time-like trajectoryin which the effective mass turns into zero. We show that it cannot beaccelerated to an infinite energy during a finite proper time under the actionof such a force. As an example, we consider dynamics of a scalar particleinteracting with a background scalar field.

Kinematic censorship as a constraint on allowed scenarios of high energy particle collisions