If metros, trams are not working, why buses?

Dubai government has shut metro and tram services for sometime in its bid to contain the spread of coronavirus. It is a good step, and would surely help in restricting the transmission of infection from people to people. However, I am seeing buses running as usual, which makes me wonder why. It is a mode of public transport, and while convenience of people must have the reason behind this move, we should also understand that it can also aid in spreading infection. There is not much distance between seats and people stand or sit close to each other.
Also, late night announcements on such moves confuse people and doesn't help. -Ramaswamy  K.G., UAE