Talking about who is in charge of what.......I think nobody knows.......
An Example........Lets cut a section across Punggol Field.......you'll see a DRAIN, next Punggol Field, a couple of LAMP-POSTS on the road, next STONE PAVEMENT, again a couple of LAMP-POSTS, followed by a GRASS PATCH, than finally our flat.
This small little cross-section, probably 50 M ? If we need to tell someone, the lights are out of order, we really don't know who to write to......ya ? The lamp-post on the road and the lamp post on the pavement, you'll be surprised that they are controlled by different ministries / Depts/people .