noun. The act of obstructing.

noun. An obstruction.

noun. Obstruction; the state of being blocked up or obstructed.

noun. The act of blocking up; the state of being blocked up.

noun. The state of being blocked

noun. A thing that is blocking

noun. the physical condition of blocking or filling a passage with an obstruction

noun. the act of blocking

noun. an obstruction in a pipe or tube

"The blockage is an emergent property of the crowd of people as a whole, and only occurs when the crowd grows to a certain size."

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