If my opponent used Banette's "Evolution Jammer" attack, can I use a Pokemon with the "Delta Evolution" Ancient Trait to evolve anyway?
No, Delta Evolution does not override Evolution Jammer.
Evolution Jammer



x2
-20
Evolution JammerYour opponent can't play any Pokémon from his or her hand to evolve his or her Pokémon during his or her next turn.

Curse DeeplyPut 5 damage counters on your opponent's Active Pokémon.
If my opponent used Banette's "Evolution Jammer" attack, can I use a Pokemon with the "Delta Evolution" Ancient Trait to evolve anyway?
No, Delta Evolution does not override Evolution Jammer.