Hi Ramesh,
I'm confused, are these filters not working? Is the system sending emails for other tasks as well?
Like I said, you would normally set up filters when you set it up, and your screenshot shows you have done this.
Or is the problem just that it takes a long time? Note that having 300,000 work items in status ready is not good for the system overall, best you look at addressing that.
Regards,
Mike