As per Census 2001, 30.66 million urban households which form 35.49% of the urban households suffer inadequate access to sanitation. According to the report of the Central Pollution Control Board (2009), the estimated sewage generation from Class-I Cities and Class-II Towns is 38254.82 million litres per day (MLD) out of which only 17787.38 MLD (35%) is being treated and the remaining is disposed into the water bodies without any treatment due to which three-fourths of surface water resources are polluted. The Ministry of Urban Development conducted a rating of class I cities on sanitation related parameters in 2009-10.Out of 423 cities, only four were in the blue category scoring more than 66 points out of 100. No city achieved the distinction of being a green city i.e. a city scoring more than 90 out of 100.
MoUD (2012): Recent Trends in Technologies in Sewerage System. New Delhi: Ministry of Urban Development, Government of India URL [Accessed: 24.03.2015]