According to AT-X channel, the airing of Gintama' episode 232 on the channel was canceled in response to the request by TV Tokyo, one of the producers of the anime. The episode was aired on TV Tokyo on October 31st.

Director Takamatsu Shinji tweeted that the episode was repeatedly rejected by TV Tokyo due to the inappropriate contents of the episode and the program data of the episode was submitted to the TV channel on the airing day. Takamatsu said "If Gintama anime cannot remain to be 'Gintama', we should rather stop airing it on TV than air something not 'Gintama'. I believe such a day won't come."

In the episode, they have joked Renho, one of the Cabinet ministers, and Ad Council Japan.

Sources: AT-X, Takamatsu's tweet

Update Nov 14th
TV Tokyo replied to the inquiry of an online media that the airing of the episode was canceled because there was a description which can be associated with a specific person. They refused to answer if there was a protest from the person.

Source: Tanteifile.com

Update Nov 18th
Takamatsu Shinji tweeted that TV Tokyo decided to cancel the airing on its own and nobody has protested against the contents.

Source: [url=http://[url=https://twitter.com/eli_ossan2/status/137509107639926784" target="_blank]https://twitter.com/eli_ossan2/status/137509107639926784[/url]]Takamatsu's tweet[/url]