sentences:  The IACS Polar Class rules were developed to harmonize the ice class rules between different classification societies and complement the IMO "Guidelines for Ships Operating in Arctic Ice Covered Waters".Traffic restrictions in the Baltic Sea during winter months are based on the Finnish-Swedish ice classes.These restrictions, imposed by the local maritime administrations, declare the minimum requirements for ships that are given icebreaker assistance, for example "ice class 1A, 2000 DWT".