The transport ministry will require temperature-sensitive stickers on airplane overhead bins starting next month to improve fire safety for spare batteries.

The stickers change color as heat rises, allowing crew members to detect fires more quickly, and each aircraft will also be equipped with at least one flame-retardant bag.

​The existing rule prohibiting passengers from placing spare batteries in the overhead compartments will remain in effect. 

The measure replaces the plastic bag policy introduced earlier this year after an Air Busan cabin fire, which was widely criticized as ineffective and wasteful before being scrapped.

In July, a lost battery on an Asiana Airlines flight slipped into the cargo hold, forcing the plane to return over fire safety concerns.

Experts caution, however, that stickers may have limited effectiveness, since once a lithium-ion battery ignites, the fire is extremely difficult to contain.