Sec 29 Cancellation

Mam, As per Sec 29(3) of CGST Act–” The cancellation of registration under this section shall not affect the liability of the person to pay tax and other dues under this Act or to discharge any obligation under this Act or the rules made thereunder- for any period prior to the date of cancellation whether or not such tax and other dues are determined before or after the date of cancellation.”

Query- 

1. What is the meaning of above provision ??
2. As per above provision — If a person applies for cancellation of gst registration on 20th March, then can he  file GSTR-3B for Feb month AFTER 20TH MARCH ALSO  as per 2nd line of above section?? 

Thanks..