The number of books being stolen from Shanghai Metro's free library scheme is falling, according to Metro authorities.

The novel plan to provide subway commuters with free books and magazines was launched in August at all 12 stations of Line 9, where commuters were allowed to pick up books or magazines, read them on their journey and return them when they got off the Metro at their destination.

However, many commuters kept their books instead of returning them. The library lost more than 500 books every day during the first week and many of those that were returned came back damaged.

Some passengers claimed they didn't know the books had to be given back and others complained about the inconvenience of returning them. Some people said they thought other Metro lines were offering the same service and planned to return the books on different lines.

After losing so many books, Metro Line 9 put up posters at all its stations explaining in detail how the scheme works and set up more boxes at every station to make it easier for people to return reading material.

The measures seem to have worked because the rate of loss has dropped from 50 percent to 30 percent. Officials said they were encouraged by the improvement and will continue the free scheme.