Behodar:I'm working from home this afternoon and just witnessed a council worker coming out to look at a drain that blocks every time there's rain. He pulled all the gunk out of it, so will it get blocked again next time? Yes, yes it will. The gunk was left in the gutter next to the drain, so will simply get washed back into it again.
In Wellington the council works dept used to have vacuum trucks clearing the stormwater sumps. Then that had to be outsourced. The contractor still has some sucker trucks but they range over a wider area. I remember a storm with widespread road flooding and all the trucks were in Palmerston North. Our street still had regular gutter clearance. With luck the drain was cleared knowing the gutter truck was due.