From Pixelmon Wiki
The use of Drought can be restricted with certain battle rules.
- Drought Clause: Pokémon with the Drought Ability cannot be used.
- Weather Ability Clause: A team cannot have a weather-setting Ability and an Ability that boosts Speed when that weather is active. This includes the combinations of Drizzle and Swift Swim, Drought and Chlorophyll, and Sand Stream and Sand Rush.
|Pokémon||Type||Ability 1||Ability 2||Hidden Ability|
|Mega Charizard Y||Fire||Flying||Drought||None||None|