Slums or just crowded places?

This article from the BBC asks the question what defines a slum.  Many who live in the crowded areas of Kolkata and beyond have TVs, bikes, go to school and work, so what makes some define their neighborhood a slum?  Almost everyone I met in India takes pride in their home and yes its crowded, but no more than some neighborhoods in New York or Orange County.  What do you think?

Article on Royal Birth announcer