  Socio-economic inequality is measured using various indices. The Gini ($g$)
index, giving the overall inequality is the most commonly used, while the
recently introduced Kolkata ($k$) index gives a measure of $1-k$ fraction of
population who possess top $k$ fraction of wealth in the society. This article
reviews the character of such inequalities, as seen from a variety of data
sources, the apparent relationship between the two indices, and what toy models
tell us. These socio-economic inequalities are also investigated in the context
of man-made social conflicts or wars, as well as in natural disasters. Finally,
we forward a proposal for an international institution with sufficient fund for
visitors, where natural and social scientists from various institutions of the
world can come to discuss, debate and formulate further developments.
