my neighbour living next door to me she has quite a number of plant display along the corridoor.
sometime if I see stagnant water reside on the plant dish I help to pour it away. To prevent mosquitoes breeding/dengue fever is a community effort. everyone has a part to play. My friend ever diagnosed with dengue fever he told me it was a terrible experience. I heed what he said.
actually you should suggest to your neighbour to take away that dish. if you take it away, it will flow into the drains straight, or the water will evaporate away slowly. the reason how they can form is because the water in the dish is collected in a small puddle. i don't have any plates beneath any of my plants. what the soil can take, they absorb. what they can't, it just flows into the drain eventually. i don't have any problem with stagnant water from plants at all.