Research into the 30 million strong Kumbh Mela, a
Hindu festival in Allahabad, Northern India on the banks of the Ganges has
overturned many old beliefs about crowd behaviour.  Even though people at the festival came from different castes and
social backgrounds, there was a strong sense of common identity.  They said this positive outlook stemmed from
a lack of the "them-and-us psychology", which was often the root of
social conflict.  "Despite the fact
the Mela seems designed to increase stress in every way – it is very noisy day
and night, very unhealthy, and very packed – what we found was that actually
people feel serene, peaceful and unstressed. 
These various findings raise very important questions about the nature
of collective participation and how it can affect both individual wellbeing and
social cohesion."

They found that people become more generous, more
supportive and more orderly rather than less. 
They contrasted a 'walk-on-by society' with a community where people are
attentive to the needs of strangers.

From the Guardian