Hello @Lekh-Chand0
I think if your local government had an issue with local water what you should have done is provided proof of this and ask Airbnb to cancel under their extenuating policy for hosts to get a free cancellation.
It sounds instead like you cancelled the booking as a host cancellation - that's why your calendar is blocked.
Please read the host EC policy and call customer services, provide proof of the government issue with local water and see if they will help/
https://www.airbnb.co.uk/help/article/990