I don't understand where the money is spent (Cities: Skylines)

I have been playing the game for 2 weeks. Before that, there was no such problem, but now he created a city, developed it to 1600 population, and then profit from 3600 began to fall to 2000. I looked at the expenses, and there this thing is. Tell me what this thing is. She has already ditched 3 cities.