Implementation of the new rules will be gradual with an initial focus on work vehicles, according to Liu Guozhang from the city's management committee. But that hasn't calmed Chinese social media users, many of whom are unhappy about the fines. "If my own car's dirty, what concern is that of yours?" asks one user on the Sina Weibo microblogging site, while another dismisses the rules as "nonsense". Others think it's a money-making scheme, and one person thinks the city authorities have bigger problems, asking: "And what are you doing about the dirty air?"