How to model a logical indicator when two inequalities hold in Integer Programming? I have an IP program where $\forall i \in I, j \in J$ my decision variables are $x_{i,j}$. I have two sets of inequalities (one inequality for every $i,j$ pair) that are of interest which are $$a_{i,j} x_{i,j} \geq 1 \ \ \ \ \forall i \in I, j\in J$$ and $$ \sum_{j \in J} b_{i,j}x_{i,j} \leq b_{i,j}- 1 \ \ \ \ \forall i \in I, j\in J$$

I now want to introduce a logical indicator variable $\delta_{i,j}$ which equals 1 if and only if both of the inequalities are true and 0 else.
How could I implement this idea by introducing appropriate constraints for my Integer Progamming model?
I was thinking about defining a variable $\delta^1_{i,j}$ and $\delta^2_{i,j}$ which equals 1 iff the first and second inequality are true respectively and then maybe combine these two auxiliry logical variables into a single variable $\delta_{i,j}$, but I couldn't figure out exactly how to make this work.
Your general approach is a good one.  Use Boolean variable that captures whether an inequality holds to define $\delta_{i,j}^1$ and $\delta_{i,j}^2$.  Then, use Express boolean logic operations in zero-one integer linear programming (ILP) to define $\delta_{i,j}$ in terms of $\delta_{i,j}^1$ and $\delta_{i,j}^2$ (via a logical-AND operation).