  The polarizations of the Y(1S), Y(2S), and Y(3S) mesons are measured as a
function of the charged particle multiplicity in proton-proton collisions at
sqrt(s) = 7 TeV. The measurements are performed with a dimuon data sample
collected in 2011 by the CMS experiment, corresponding to an integrated
luminosity of 4.9 inverse femtobarns. The results are extracted from the dimuon
decay angular distributions, in two ranges of Y(nS) transverse momentum (10-15
and 15-35 GeV), and in the rapidity interval abs(y) < 1.2. The results do not
show significant changes from low- to high-multiplicity pp collisions, although
large uncertainties preclude definite statements in the Y(2S) and Y(3S) cases.
