We consider a multi-cell MIMO downlink (network MIMO) where $B$ base-stations (BS) with $M$ antennas, connected to a central station (CS), transmit $K$ messages to $K$ single-antenna user terminals (UT) simultaneously. Although many works have shown the potential benefits of  network MIMO, %the BS cooperation in the multi-cell downlink
the conclusion critically depends on the underlying assumption of perfect channel state information at transmitters (CSIT). In this paper, we propose an outage-efficient strategy that requires only partial CSIT. Namely, with side information of all UT's messages and local CSIT, each BS applies zero-forcing (ZF) beamforming in a distributed manner, which creates $K$ parallel MISO channels. Based on the statistical knowledge of these parallel channels, the CS performs a robust power allocation that jointly minimizes the outage probability of $K$ UTs and achieves a diversity gain of $B(M-K+1)$ per UT. Numerical results show that even with partial CSIT network MIMO can be beneficial by providing high data rates with a sufficient reliability to individual users.