Study setting
A cross sectional survey was conducted in three urban slums in India’s national capital, Delhi, between November 2010 and March 2011. The detailed description of the study area and sampling method are described elsewhere [17]. Briefly, the three urban poor clusters namely CPJ, Buland Masjid and Chanderpuri were from three constituencies of North-East district of Delhi. This district is home to the highest number of slum dwellers compared to other districts of Delhi state.