Amid the frenzy of PM Narendra Modi's politically astute launch of the Swachh Bharat Abhiyan or the Clean India Campaign to coincide with the vision of Mahatma Gandhi on his birth anniversary, we bring you the voices of the safai karamcharis or the sanitation workers, who are from the bottom of the caste system - the invisible people who do some of the dirtiest jobs of keeping our country clean and have little or no rights. How do they look at this campaign - with hope or disappointment?