In one sentence, describe what the following article is about:

The trick is to get its health below that percentage without letting it faint. Use a combination of weak and medium power attacks to do this. See the numbers after each technique? These are called the Power Points or PP. Generally, the higher the PP, the weaker the attack. In these games putting Pokémon below 33% HP does not increase the catch rate further. Poisoning or burning the wild Pokémon will cause its HP to gradually deplete, making it easier to catch, but increasing the risk of causing it to faint. Putting it to sleep or paralyzing it are more reliable methods, however sleep only lasts a few turns and paralysis still allows it to fight back sometimes. If you can freeze a Pokémon, you can catch a Pokémon very easily, because in Generation 1 (Red, Blue and Yellow) the only way to thaw a Pokémon is to hit with a Fire-type attack.

Summary:
Reduce the Pokémon's HP to 33% percent or lower. Use status ailments.