Anna Hazare is an Indian anti-corruption activist. He had planned an indefinite public hunger strike to protest the Indian government's failure to deal with corruption. So, the government arrested him. Then, just to prove their point, they arrested 1300 of his followers.
The pretext is of course "public order". Apparently the Indian authorities believe that a peaceful sit-down protest is the same as a riot, which must be suppressed. But the natural conclusion is that they don't like what Hazare is saying and want to shut him up, that they are dirty and have something to hide.
The good news is that freedom of expression (including the right to protest) is affirmed in the Indian Constitution. Now we'll get to see if that document actually means anything, or if it will be ignore dby those in power to protect their own corrupt interests.