The legal provisions regarding the right of lien of an unpaid seller has been stated from
Sections 47 to 49 of the Sale of Goods Act, 1930 which may be enumerated as follows :

(i) According to Section 47 the unpaid seller of the goods who is in possession of them is
entitled to retain possession of them until payment or tender of the price in the following
cases namely :
(a) where the goods have been sold without any stipulation as to credit.
(b) where the goods have been sold on credit, but the term of credit has expired; or
(c) where the buyer becomes insolvent.
The seller may exercise his right of lien not withstanding that he is in possession of the goods
as agent or bailee for the buyer.

(ii) Section 48 states that where an unpaid seller has made part delivery of the go ods, he
may exercise his right of lien on the remainder, unless such part delivery has been made
under such circumstances as to show an agreement to waive the lien.

(iii)  According to Section 49 the unpaid seller loses his lien on goods :
 (a) when  he  delivers  the  goods  to  a  carrier  or  other  bailee  for  the  purpose  of
transmission to the buyer without reserving the right of disposal of the goods.
(b) when the buyer or his agent lawfully obtains possession of the goods ;
(c) by waiver thereof