A 45-year-old woman is to be hanged on Friday for trafficking around 30 grams of heroin, but Amnesty International says there is no evidence the death penalty is a deterrent but Singapore insists it is effective.

A 45-year-old woman is to be hanged on Friday for trafficking around 30 grams of heroin, but Amnesty International says there is no evidence the death penalty is a deterrent but Singapore insists it is effective.