From Bulbanews, your community Pokémon newspaper.
First six episodes now available in Japanese
The first six episodes of Pokémon Generations have been released in Japanese on the official Japanese Pokémon YouTube channel. There is no indication of when further episodes will be released in Japanese.
The two episodes of Pokémon Generations were released in European languages on September 16, 2016. Episodes have been released in European languages every week since then, and will continue to be until December 23, 2016, for a total of 18 episodes. Currently, 16 episodes have been released.
The playlist of episodes in Japanese can be found here, while the playlist of episodes in English can be found here.