2004 law actually bans chewing gums

When heading to Singapore, leave the Juicy Fruit at home and pop a breath mint instead. Among the lengthy list of items that aren't allowed to be imported into Singapore is chewing gum, a rule enforced in order to keep public spaces clean. An exception is made for dental or nicotine gum. (14 strange laws from around the world; Cassidy Hopkins; Jul. 7, 2016, 1:42 PM)

There is a ban on importing chewing gum into Singapore which is strictly enforced. Since 2004, only chewing gum of therapeutic value is allowed into Singapore under the "Regulation of Imports and Exports (Chewing Gum) Regulations". The exception is made for dental or nicotine gum.(Wikipedia) Gum can be bought from a doctor, but must be prescribed.

According to the Regulations, "importing" means to "bring or cause to be brought into Singapore by land, water or air from any place which is outside Singapore [...]" any goods, even if they are not for purposes of trade.(Wikipedia)

Under the rule, no gum is allowed to be bought or sold inside Singapore and there is a $700 fine for spitting out gum on the streets. (Wikipedia)