Neither look very good for an upgrade to Polaris, when looking at the fares left. However, if you’re in Y and looking for an upgrade into PP, the ORD-DEL flight looks better right now since there are PP seats left (O9) and Y seems to be full.
If you’re trying to upgrade from Y to Polaris, not looking good for either flight, since the PP to Polaris crowd will upgrade ahead of you.