Answer
$P_1$ is negative and at the point $P_2$ is positive.
Work Step by Step
Divergence Theorem: $\iiint_Ediv \overrightarrow{F}dV=\iint_S \overrightarrow{F}\cdot d\overrightarrow{S} $
where, $div F=\dfrac{\partial P}{\partial x}+\dfrac{\partial Q}{\partial y}+\dfrac{\partial R}{\partial z}$
The divergence will be negative when the net flow of water towards the inside and when the net flow of water is outwards, then the divergence at that point gets positive.
Also, The divergence will be zero when there is net flow of water either inwards or outwards.
We found that at the point $P_1$ that the net flow of water is inwards, thus, the divergence is negative and the divergence at point $P_2$ is positive.
Hence, we get $P_1$ is negative and at the point $P_2$ is positive.