Densely

The ants formed a densely packed line as they carried food back to their colony.

The densely populated areas are prone to traffic congestion.

The train compartment was densely packed with commuters during peak hours.

The densely packed train during rush hour was overwhelming.

The subway train was densely packed with commuters during rush hour.

The city is densely populated with tall buildings.

The city streets were densely packed with cars during rush hour.

The city's downtown area is densely populated with tall skyscrapers.