  The atmospheric neutrinos produce isolated neutral pions ($\pi^0$-events)
mainly in the neutral current interactions. We propose to study the ratios
involving $\pi^0$-events and the events induced mainly by the charged currents.
This minimizes uncertainties related to the original neutrino fluxes, and in
certain cases, also to the cross-sections. Experimental study of these ratios
will allow one to check the oscillation solution of the atmospheric neutrino
problem and to identify the channel of oscillations. Illustrative analysis of
existing data is presented.
