why are overcrowded and poorly  ventilated areas a major factor in tje spread of air brone diseases ? [for 1 mark]

In overcrowded areas there are greater chances of a person infected with the disease spreading the infectious droplets through breathing or sneezing. So there are chances of a healthy person inhaling that. Also if the area is closed and not properly ventilated then infectious droplets will keep on circulating within the closed area infecting many people. So the chance of spreading  air borne diseases are more in overcrowded and poorly ventilated areas.