Banned episodes

A few episodes of the Pokémon anime have been banned for a specific reason:

Denno Shenshi Porygon (Electric Soldier Porygon)
This episode is infamous for causing many seizures when first aired. In the episode, Pikachu, in order to stop some missles, uses a Thunderbolt attack. This leads to a very large and quick sequence where lights flash very quickly and vividly on screen (the light flashing is very similiar to an attack PSI from the Mother series called PSI Flash except it didn't cause uncontrollable crying, Numbness or Strangeness. However some of the victims did faint). Some of these lights were strobe lights being flashed at very high speeds. Many viewers reported dizziness and nausea as a result of this. 685 children were taken to hospital, although only 150 were kept overnight for observation. Also despite rumors there is no evidence to suggest that any of the viewers suffered lasting injury.

The episode has never been shown again and has set guidelines for flashing lights in anime. To remove the episode from the public mind, the character Porygon has never appeared again over the course of the series.

The Legend of Dratini
This episode is banned due to Kaiser pointing a gun in Ash's face and threatening to shoot him and because of Jessie, James, and Meowth shooting Kaiser to catch the Dratini. The episode also contains profanity (for example, James swears at Kaiser.) Also, there is a mistake when Ash says he found a Rhydon, whereas he actually found a Rhyhorn. Later in the episode Misty mistakenly refers to her Staryu as a Starmie.

Yureru Shima no Tatakai! Dojoach Vs Namazun!!
This episode revolves around a bunch of Whiscash causing an earthquake. It was removed and never aired anywhere, including Japan, due to similarities to the Chuetsu earthquakes of October 23, 2004.

Rocket Gang Vs Team Plasma Parts 1 and 2.
This episode was in Japan but was delayed in the United States because they was an 9.0 earthquake that happen in Japan which also caused a Tsunami.

Beauty and the Beach
This episode revolves around all the female characters entering a swimsuit competition, including James, who, in order to enter buys a pair of inflatable breasts. The episode is notable for one scene where James is waving his fake breasts in other's faces for comedic effect. The image has become a quite popular GIF on the internet. The scene that got it banned was removed from the english episode, but it was badly cut however.