Seems to have become the weapon of choice against dissidents. He's been hospitalised and is in a very serious condition and has lost his sight. There's a lot of mutual animosity between Pussy Riot and the Russian government and members have served time in prison in the past for their stance against the government. They've got a lot of guts standing up against Putin even if you don't approve of their methods.
https://www.google.co.uk/amp/s/www.bbc.co.uk/news/amp/world-europe-45505064
https://www.google.co.uk/amp/s/www.bbc.co.uk/news/amp/world-europe-45505064