Please see this very interesting scholarship.
The Calcutta Research Group recently finished a study on “Cities, Rural Migrants and the Urban Poor”, highlighting the plight of migrant workers in three Indian cities, Mumbai, Delhi and Kolkata. The link to the report is: http://www.mcrg.ac.in/Rural_Migrants/Final_Research_Briefs.pdf
And the link to the details of the study is: http://www.mcrg.ac.in/Rural_Migrants/Rural_Migrants_concept.asp
The Economic and Political Weekly published a set of four of the papers and a brief introduction to them: http://www.epw.in/migrants-and-city