Registration Cancellation Query

Khuda Baksh (40 Points)

05 December 2018  
Dear Team,
I had started business on July 2018, in a month of August my turnover was 3,00,000 but after Aug till now I don't have more transactions and I want to cancel my GST registration.

Could you please tell me I have to file GSTR10 or no need.

And pls let me know if is there any majore Changes which is mandatory to cancel GST.

Thanks in Advance.