Auction of gair marusi agriculture land in punjab by bank with physical possession under sarfarasi

No.  Gari marusi lands are temporarily given to the tenants for a specific period.  The tenants have no right to sell/transfer the land. 

Gair Marusi refers to non-occupancy tenants who do not have the rights associated with occupancy tenants under the Punjab Tenancy Act, 1887. The term literally means non-occupancy, indicating that such tenants cannot claim the status and rights of occupancy tenants.

They are non occupancy tenants  and  are essentially tenants-at-will and cannot claim ownership or adverse possession. 

If that is the case the banks cannot acquire title to the property just because the loan repayment was defaulted.

It is advisable that you better obtain proper legal opinion from an experienced lawyer in the local and proceed only if recommended

How the Bank had taken gair maurusi land documents to create equitable mortgage, where title of the subject land was not with borrower.

I will  advise not to bid for such land.

Don't bid for said land.