That is a very bold step from Ravichandran Ashwin. The BCCI doesn't permit Indian players to participate in foreign leagues if they are active. Ashwin need to "retire" from all forms of cricket before he becomes eligible to play in these competitions. And that will put the BCCI in a spot of bother. In case Ashwin has retired, how he continues to play in the Hundred? So far they have allowed players to play in the legends series, but those are mostly players who are in their mid-40s and 50s.
I think this is good rule to play in foreign leagues like The Hundred, Indian players like Ravichandran Ashwin must officially retire from all forms of Indian cricket both at home and abroad. But this rule puts BCCI in difficult spot because it shows how much other leagues want their top players. And BCCI has strict rules to keep Indian Premier League and its own cricket strong many international T20 leagues now offer good opportunities for skilled players who are no longer on national team. Fact is that great player like Ashwin is making this decision shows how appealing these other leagues have become and it is problem BCCI will have to deal with going forward.