Negative Binomial Distribution (NBD) has been shown to fit the charged particle multiplicity distributions obtained in various hadron-nucleus collision experiments at energies E lab = 6.2 to 800 GeV. The inverse of NBD-parameter k shows a logarithmic increase with CM energy, [Formula: see text] which is different from that in elementary collisions. It has also been shown for the abovementioned reactions that the average size of the 'clan' increases with energy. The investigation of clan structure in π− + Em reaction shows that the clans are more numerous but smaller in size in the forward than backward hemisphere.