0 - CBD
1 - West Coast: Telok Blangah, West Coast,
Clementi, Bt Merah, Holland
2 - Jurong: Jurong, Tuas
3 - Lim Chu Kang
4 - North-west: Bt Batok, Choa Chu Kang, Bt
Panjang, Bt Timah, Woodlands
5 - Central: Ang Mo Kio, Bishan, Toa Payoh,
Yishun, Sembawang
6 - North-east: Punggol, Sengkang, Hougang,
Serangoon
7 - Eastern 1 (north of PIE): Pasir Ris, Tampines,
Bedok Reservoir, Kaki Bukit, Paya Lebar
8 - Eastern 2 (south of PIE): Bedok, Geylang,
Eunos
9 - East Coast: Changi Airport, Loyang, Simei,
Siglap, Joo Chiat, Marine Parade, Tg Rhu
Also realised that the last digit of the code would be either 1
or 9, and for opposite roads, they would be opposite. Means
if here is 91081, opposite is 91089. (cant confirm,
mostly)
Second/third digit will determine the area even more
distinctively.