Dispute over Niti Aayog meeting, why are many opposition chief ministers boycotting it?

Niti Aayog meeting is going to be held today. Chief Ministers of many states are not coming to this meeting. Mamta Banerjee has given a statement before attending the meeting. She said that she will talk about the rights of Bengal in the Niti Aayog meeting. Hemant Soren is also going to attend this meeting.